>> you can almost recreate the crime. >> right there on the wall, a mystery scrawled in blood. three cryptic letters. what would you make of this? >> is that a word? is that a person? >> the clues pointed to so many directions that it was a total mystery. >> the case, the murder of a former model and flight attendant. >> when she got dolled up, oh my god, gorgeous. >> did she write these letters? was this a hint to who killed her? >> this is a message saying this is my killer. >> like you would see in a movie. >> and the ending, that was just like a movie, too. >> i can't believe what people do to each other. hello, and welcome to "dateline." >> roc, in this case, those three letters would tell a story all their own. when karen pannell was found murdered in her south florida home, the letters scrawled in blood above her body seemed like a beacon that could lead detectives to her killer. but what exactly did they mean? what other crucial clues were in sight? it would take dogged specialist with a keen eye to unravel this mystery. here's dennis murphy with "written in blood." >> if year-round sun and water is your thing, florida's west coast should be high on your list of places to live. it was for one-time model and flight attendant got sand in her shoes, she never looked back. >> she loved the beach, diving, boating, that life. >> her friend worked the counter at american airlines in tampa with karen. if you were a frazzled passenger -- who isn't these days -- karen is the antidote. exactly the right agent to bump into to get you on your way. >> karen was very pretty. she was smart. smiled all the time. funny. >> but when the always capable and reliable karen didn't show up for her saturday morning shift on october 11th, 2003, clearly something was wrong. her boyfriend had tried calling her at home. >> when she wasn't at work or answering her calls, i began to get worried, but it was a couple hours before i really got panicky about it. >> the boyfriend drove over to karen's condo, the front door was unlocked. a bad sign. he said he stepped inside and looked to the right to the kitchen. >> i saw her body and i knew immediately, there was no doubt in my mind she was dead. i picked up the phone and i called 911. >> she's laying on the floor, there's blood everywhere. >> karen pannel, sprawled on her back, bloody. a murder victim in her own home. >> when the first deputies arrive on the scene, her boyfriend is in the front yard, he was hysterical. he actually threw up he was so upset about finding his girlfriend. >> depuies gave tim, the shaken boyfriend, a chance to collect himself in the back seat of the police car. he placed a call to her friend katherine with the unimaginable news. >> karen, it's tim. i'm at karen's apartment, she has been stabbed. >> stabbed? >> it's a horrible way, it's very horrible way to die. >> karen, the baby of the family with five older brothers suddenly gone. she had been especially close to her oldest brother mike. >> my brother called me. i was at the airport, and said, you better sit down. he said, karen's been murdered. >> any theories about what happened? >> i don't know. i was trying to figure out the why and relying on the police to do what they needed to do. >> and what they had to do was plenty. they processed the crime scene, filmed every inch of karen's home, knocked on doors, tried to figure out just who their victim was. detectives holbrooke and larry nelvin began with the man that made that 911 call. >> the first thing a lead investigator will do is talk to the people closest to her. in this case, we had timothy permente finding his girlfriend. we took mr. permenter back to the office and talked to him extensively. >> tim, a car salesman, gave them a run down in the hours leading up to the terrible discovery. he said he popped in briefly on karen the night before to drop off a gift. a photo calendar of kittens he knew his cat lover girlfriend would find irresistible. tim said he left around 7:30. that was the last time he saw karen alive. >> wouldn't it have been your routine to stay the night? >> not on a friday night. she had to go in work the next day. >> after saying good-bye, he said he ended up spending the night with friends, about an hour to the north. >> is he saying anything, he can't do it? i know boyfriends are figured suspicions, i want to talk to a lawyer? >> no, he's being more than cooperative. >> while tim says he was off with his friend, there appeared to have been a frenzied struggle at karen's house. forensic specialist, anna cox, assessed the aftermath. >> she put up a heck of a struggle. >> what are you looking at? >> she had defensive wounds, the way her body was contorted. i just remember thinking, she put up a heck of a struggle. she really fought for her life. >> do you think oh my goodness or have you seen anything different at this point? >> i can't believe what people do to each other. it was terrible. it's terrible. >> around back, cox, the crime scene tech, found the security bolt on a sliding glass door had been dislodged. there were other signs of tampering. >> there was a cable box that was open. you start to think to yourself, somebody's trying to cut the wires. there was a knocked over bird bath. so there was evidence outside that at first you need to think to yourself, i think that this might be a burglary. >> and karen's overturned purse on the stovetop supported the break-in theory. anna cox took an inventory of everything at the crime scene. a pizza box, a garden glove, a grocery receipt, all routine findings so far. but it's what authorities spotted next on the wall just above the body that would turn this case into something out of the movies. a three-letter message in blood. you didn't have to squint to make it out, either, roc. on the victim, karen's right hand index finger was clearly stained with blood. roc. what was the murdered woman try to tell the cops? >> all these theories were running through my mind? what does that mean? is that a word? is that a person, a thing? the clues pointed in so many different direction, it was a total mystery. >> there's a concept in the law known as a dying declaration. with those three letters scrawled in karen's own blood lead to the apprehension of her own killer. >> coming up, investigators dig into that three-letter mystery. who or what was roc? when "dateline" continues. with nurtec odt, i can treat a migraine when it strikes and prevent migraine attacks, all in one. don't take if allergic to nurtec. allergic reactions can occur, even days after using. most common side effects were nausea, indigestion, and stomach pain. ask about nurtec odt. and we're done. hm, what about these? ♪ looks right. [sfx: spilling sound] nooo... nooo... nooo... quick, the quicker picker upper! bounty absorbs spills like a sponge. and bounty is 2x more absorbent so you can use less and get the job done with one. this works. kind of. bounty, the quicker picker upper. the camera always liked karen dennis murphy (voiceover): the camera kind of. always liked karen pannell. she was both hard to miss and hard to forget, just ask her pannell. she was both hard to miss and hard to forget. just ask her boyfriend tim permenter, who was smitten right away when he met her at the dealership where he worked. what did you think of her? >> she was gorgeous, she was beautiful. >> you were pinching yourself. you thought you were the luckiest guy. >> i thought she was the one. i thought she was the one i could settle down with. >> settling down hadn't been part of karen's growing up. she and her five brothers had been raised as military brats and moved bases a lot. now they were traveling from far flung parts of the country for her funeral. shocked and in mourning for the lost sister who had always been their glue. >> all the boys kind of got involved in their own stuff. then there was karen. she was really what connected all of us to the family unit. >> what does that tell us about her? >> she was really more important to us than we knew. i think she was always more interested in family as a whole than she was in herself. >> brother mike wasn't alone in thinking his kid sister could have been a sky's the limit person. >> she could have been anything she wanted, a scientist or a doctor or whatever. >> well, her friends loved her. >> and she was hard not to love. >> even harder to forget what a cruel fate she had suffered at the hands of a killer unknown. >> during the viewing, there were invisible stab wounds on her hand. you know, so we kind of pulled flowers down a little further. >> a few days after the murder her many friends at the airport said their good-byes. >> there's a chapel in the main terminal at the airport. there were so many people there from so many different airlines, the security people. it was incredible. >> meanwhile, the pinellas county sheriffs investigation was moving quickly on several fronts. first, they validated boyfriend tim's story. he said after visiting karen early that evening, he spent the night with a friend, george solomon in moon lake, about an hour to the north. >> he did, in fact, go up to where george was staying with his girlfriend if pasco county. there was confirmed by george and george's girlfriend. george gave us a time line consistent with what permaner gave us. >> tim's story on the night of the murder checked out. and he voluntarily came clean about something. he had a record. he had done time. >> early on in your life, you get in trouble. what was going on with you? >> i was running an escort service. got stupid, started it up small, basically, running an ad out of a newspaper, getting a small office. and it just expanded from there, it ballooned. >> what kind of money were you pulling down a week? >> i was grossing about 6,000, $7,000 a day. >> a day? you were how old? >> 20. that's the trap. why am i going to school when i'm making this kind of money? >> why go straight, huh? >> yes. >> it ended up in a gunfight? >> yes, sir. >> tim says he was worried he'd be painted as a bad guy right away because of his sorted past. so he promised to cooperate in every way possible, and the cops took him up on it. >> i allowed them to photograph me. removed my clothing. i allowed them to go to my home. take anything they wanted. >> there was nothing about his clothing, his car, his person that led to us believe that he was involved in any other way than he said he was. he came over to see her, found her and was devastated. >> tim permenter's alibi checked out. police dismissed any clues pointing to a home invasion. after all, karen had been stabbed 16 times, an attack so ferocious, it could only be a crime of passion. now the detectives were desperate to figure out what their biggest clue of all meant, those three letters written in blood. roc. this is a creepy scene. i mean, you got this scrawled in blood message saying this is my killer. i'm now dead, you find this guy. that's what it's suggesting, isn't it? >> absolutely, it's what it's suggesting. just like you would see in a movie. >> detectives soon discovered how those letters on the wall, roc, were, in fact, connected to the victim lying beneath them. roc, it turned out, was a man that spelled trouble for karen in the past. >> roc was an ex-boyfriend karen pannell had problems with previously. >> and whoever and wherever thi roc was, he'd just b prime . they ha off t>> to find>> to >>n accomplished. murder. >> when "dateline" continues. rder >> when "dateline" continues caplyta treats both bipolar i and ii depression. and in clinical trials, movement disorders and weight gain were not common. call your doctor about sudden mood changes, behaviors, or suicidal thoughts. antidepressants may increase these risks in young adults. elderly dementia patients have increased risk of death or stroke. report fever, confusion, stiff or uncontrollable muscle movements which may be life threatening or permanent. these aren't all the serious side effects. caplyta can help you let in the lyte. ask your doctor about caplyta. find savings and support at caplyta.com. my frequent heartburn had me taking antacid after antacid all day long but with prilosec otc just one pill a day blocks heartburn for a full 24 hours. for one and done heartburn relief, prilosec otc. one pill a day, 24 hours, zero heartburn. my mental health was much better. but i struggled with uncontrollable movements called td, tardive dyskinesia. td can be caused by some mental health meds. and it's unlikely to improve without treatment. i felt like my movements were in the spotlight. #1-prescribed ingrezza is the only td treatment for adults that's always one pill, once daily. ingrezza 80 mg is proven to reduce td movements in 7 out of 10 people. people taking ingrezza can stay on most mental health meds. ingrezza can cause depression, suicidal thoughts, or actions in patients with huntington's disease. pay close attention to and call your doctor if you become depressed, have sudden changes in mood, behaviors, feelings, or have thoughts of suicide. don't take ingrezza if you're allergic to its ingredients. ingrezza may cause serious side effects, including angioedema, potential heart rhythm problems, and abnormal movements. report fevers, stiff muscles, or problems thinking as these may be life threatening. sleepiness is the most common side effect. it's nice. people focus more on me. ask your doctor about #1 prescribed, once-daily ingrezza. ♪ ingrezza ♪ (carolers) ♪ iphone 15 pro for your husband! iphone 15 pro — ♪ (wife) carolers! to tell me you want a new iphone? 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(carolers) ♪ we tried to tell him but he paid us a lot... ♪ (husband) it was a lot... ♪ mhmmm ♪ (vo) this holiday turn any iphone, in any condition, into a new iphone 15 pro with titanium, apple tv 4k, and six months of apple one. all three on us. it's holiday everyday with verizon. a stomach churning crime scene, dennis murphy (voiceover): a stomach-churning crime scene with an, at first glance, cryptic with a cryptic message in blood. roc. roc was the unusual but proper spelling of karen pannell's ex-boyfriend. so tell me about the former boyfriend known as roc, letters scrawled in blood. who was he? >> roc was an ex-boyfriend. he had a little legal problems, a little substance abuse problem. >> roc had a personality as big and as loud as the pipes on the harleys he loved to cruise. he worked at an auto body shop handling claims. when he met karen, she was on a downward spiral. after being married five years, she recently had got an divorce. the doctor had given her awful news. she had multiple sclerosis, 38-years-old. >> to be a young, divorced woman, with this awful diagnosis, what do you think that did to her? that's a lot to put on your shoulders. >> right. i think that really affected her self esteem. frankly, i think it had an impact on the kind of men she was attracted to. >> karen came to rely on roc to take her to doctor's appointments and give her injections. but when she took the step of asking him to move in, her friends and family thought she was asking for trouble. >> i think that's true. but then is it my place to say, well, you need to go find somebody that is going to offer you a better future? >> you can't dictate terms to your kid sister? >> no, you can only fix yourself. >> as it turned out, roc wasn't a fix for karen either. the relationship soon took an ugly turn. >> they seemed to get along for a while and she was happy. and he turned into not a very nice guy. he was a little creepy. >> he was tough on her? >> there were some unexplained bruises. i used to tell her, what are you doing? he did not deserve her. she wouldn't listen. >> the fights got worse and police were called three separate times to intervene. one time roc allegedly broke down the front door. that was the last straw. karen filed a domestic battery complaint and roc moved out. tim says even a year later, he was still harassing karen about a rolltop desk he left behind. >> she was starting to get scared of him towards the end. >> the issue he had was i got a valuable piece of furniture, i want it back. >> right. but karen said that that was a ruse. >> trying to worm his way back in? is that the way she saw it? >> that's the way she put it to me. >> they knew they had to confront this roc, so they tracked him down and paid a surprise visit. he wasn't happy to see them. >> i'm in the garage of my home in north port, florida. unmarked car shows up, everybody know what is that is. i'm thinking, what the heck is that? >> detective holbrooke identified himself and said they need to talk to him about his friend karen. >> we sit down on the porch and he goes, well, she's dead. of course this doesn't register. and i just said you need to tell me what's going on. >> but the detective wanted roc to do the talking. he asked about his troubled relationship with karen. >> roc indicated that he was using drugs and that karen liked to drink and that they fought often. >> roc said he savored the good times with karen, too. >> when she got dolled up, oh, my god, gorgeous. i mean, picture perfect. wasn't anything out of place. >> were there some sparks there, roc? >> yeah, there was, she was all that, just by herself and ready to go. she looked hungry for attention and she was alone and it was perfect. it was a perfect setup. >> what do you think she saw in you? what was working from her side? >> probably the bad boy kind of thing. i wasn't your conventional straight-laced kind of guy. >> roc was open with the detectives. even came across as a good guy. but conceded there were screaming matches with karen and a few rip roaring fights but said she was the instigator. >> she'd get violent, physically violent. just stuff. things would happen. but nobody ever got arrested, but they'd come out. they would address the issue. >> as roc tells it, she gave as good as she got. he dodged a few pieces of thrown crockery. >> she was ready to stand up for herself at the drop of a hat. she was a tough girl. >> roc remembers karen playing hardball about that rolltop desk of his, too, not liking her attitude. >> i did call her on several occasions about my rolltop desk. >> the desk. >> that stupid desk and it was bugging me. i mean, it was a nice piece of furniture and i wanted to get it back. she pretty much said, you left, you're not getting it. >> he never did get. that roll top was still in karen's condo on the night she was stabbed to death. now, detective holbrooke pointedly wanted to know if roc had been there too. >> he says, where were you on such-and-such a day. i'm like, well, first of all, i'll have to look at the calendar because i don't know where i was that day but i guarantee you i wasn't in oldsmar. so we go from there to discussing where i was, who i had been with, where i lived. >> so are you getting a serious grilling? >> right. he ends up telling me that we found your name in blood on the wall. >> roc? >> yeah. so, obviously, i'm a suspect. i acknowledge that. i mean i'm looking at murder. i'm getting somebody's talking to me about a murder. >> roc waived his right to a lawyer and agreed to give fingerprints and swabbing. it looked as though police found yet another cooperative boyfriend of the victim. >> i said, if you are looking for fingerprints, they're all over that home. i lived there for a year, so you're going to find them. >> did you lose your patience? >> i did lose my patience when they cut the end of my finger off taking a fingernail. you take the end of my finger off, now i'm done. >> roc's cooperation had an edge to it. was he really trying to cover his tracks? detectives were d