Lurking, a car speeding through the neighborhood, and there were footprints out behind the house. Putting alarms on every door because somebodys out there. But detectives, they decided the killer wasnt out there, but inside the house. Now, with one of their own under arrest, the family was furious. You see these people . This is love. This belief in this human being. Please listen to us. Did investigators rush to judgment . Do you have any idea beyond your own fevered imagination thats what happened . You dont have a clue. I this i that i do have a clue. Was the real killer still out there . Im lester holt, and this is dateline. Tonight, Keith Morrison with a killing in cottonwood. On the afternoon of may 4th, 2012, casey duenas walked out onto the field for the start of his very favorite thing, high school baseball, a double header. Spring was in its full glory here in Northern California. His senior year was almost done. This was the place he loved, the game he loved. People sometimes talk about having premonitions of things. Did you have anything like that at all . It was just another day, it was just another one of my countless baseball games, countless baseball games. Wasnt of course, though no one knew it as though wiled their way through a golden afternoon. Redding, california, with its famous sun dial bridge, its parks, its Middle America feel, is a whole different place, a different life than the california whose reputation blares technicolor from the narcissism to the south. Drive a few minutes from redding and youre on the ball diamond at a little place called cottonwood, here at the anchor of mt. Shasta, just like they knew their mother would be in the stands. They were there . Both of them. Always there . Always there, never missed a game. His parents, mark and karen duenas, side by side by the dugout, as always. They were together since they were, what, 17 years old . They practically lived in each others skin . Exactly. His mother had brought the chocolate chip cookies she passed out to the players after every game and for which she was justly famous. His father made sure he finished work in time for the opening pitch. What kind of parents were they . They were the best parents that you could ask for. This is jason, their eldest son, and here the photo of jasons graduation with his proud parents the day he became a fireman. They would do anything for us and they did. Mark and karen were from big mormon families, High School Sweethearts who married as teenagers and watched their own brood quickly expand, all boys, jason, jacob, tyler, troy and casey, boys bursting with testosterone. It was a rowdy house. We had Football Games inside the house. We were egged on by our parents and they loved it. Karen was a full time mom and once the boys were old enough, taught parttime at nearby shasta college. For decades mark got up at 2 00 a. M. To drive for u. P. S. , just because it freed him to coach his sons teams come afternoon and to spare his wife middle of the night disruption mark slept in a separate bedroom, had for years. My dad treated her better than anybody could treat their wife. My mom was the queen. They lived simply. They lived paycheck to paycheck. They never had a lot extra. Son tyler. For them it was all about family . Yes, always. They all stayed as close as any family could be, when jason got married, he moved into the house right next door. Helped celebrate mark and karens Silver Wedding anniversary as they all did. By 2012, they were grandparents many times over, had been married nearly 33 years. One thing i always looked up to and loved about their relationship was that they still dated. Tylers wife, tina. After that long, sometimes you can lose that, and i never saw them lose that. But change does come for everyone and by 2012 in their early 50s, mark and karen were making some changes. Karen went back to school, Nursing School. This was a plan that they had talked about . It was the perfect situation. She got to stay home with the kids all growing up, and now she was ready to start her career. If you think about it, a pretty dang good plan. He worked his whole life, he could start his own business while collecting a pension, and then she would, you know, start her career in nursing. Not so easy, of course, Nursing School is a tough thing, and not just for karen, either. Her brother, joe and wife, jackie. Well her commitments changed, having grandma there when you need her or having mom there when you need her, shes going to have to study. And she was struggling with the classes. She felt like she should be doing better but i remember a text that said i just got back from the er and got the chance to work with people finally and i love it. So she was on her way. She was really on her way. So that may the 4th casey joined his parents at home after his ball game. Then, it being friday night, he and a friend went to see a movie the avengers. Started up at 9 15, and told my parents everything was fine. Do you remember the last thing you said to your mom . She handed me a 20 bill and i thanked her and hugged her goodbye. It was late when casey returned, and almost immediately fell asleep. Then what do you remember next . Put my head on the pillow and two seconds later dad is at the door freaking out. And seconds later 911, your emergency . The duenas family was about to discover that a perfectly ordinary evening had ended in tragedy. Shes got blood everywhere. Everywhere. When we return, a dad devastated. Is one tragedy about to become two . I remember him coming in the door and just collapsing. Falling on the floor. If youve got a life, you gotta swiffer sure shutup i can do that do i have to . I dont want there to be white marks. Good bye beautiful dress i never got to wear. Nothing no dust, theres no marks. Its really dry what is this . Oh my god, its dove i knew it its a 48 hour antiperspirant. No white marks. On a 100 colors. I would absolutely use this. I think you converted me clearasil rapid action begins working fast for clearly visible results in as little as 12 hours. Wow but what other teen problems can it fix fast . Will clearasil act fast to help this teen concentrate on his math test . Darn it only worked on the acne. Can it hel. Nope. No. So lets be clear clearasil works fast on teen acne, not so much on other teen things. And now theres new clearasil overnight spot patches with patented technology for faster healing. [car[clicking of ignition]rt] uh wha woof eeh woof wuh [silence] [engine roars to life] [dog howls] dramatic opera music swells from radio [howling continues] you give us comfort. And we give you bare feet. I love you, couch. Backsweat and gordos everything. I love you, but sometimes you stink. New febreze fabric refresher with odorclear technology. Cleans away odors like never before. Because the things you love the most can stink. And plug in febreze to keep your whole room fresh for up. To 45 days. Breathe happy with new febreze. Do you think im gonna crack under pressure or conquer the field . Defy expectations any day with always infinity. Made with flexfoam. Absorbs 10x its weight. Rewrite the rules. Always. It was 12 30 a. M. , now may 5th, 2012. Casey duenas, home from a movie and late dinner with friends, opened the front door, unlocked as usual, and moved quietly down the little hallway toward his bedroom. Had it not been so late he might have stopped by his mothers room to say good night, but the house was dark, everyone asleep, so it looked to an exhausted casey who fell into bed and almost immediately into a deep sleep, and then 25 minutes later dad is at the door, freaking out, go next door, go next door, go get jason. Somethings happened to your mom. Go get jason. Jason ran next door to his brother jasons house. 911 your emergency. While his father mark beside himself called mmg. She i came in shes got blood everywhere. I have no idea. You have no idea what happened . You dont know where shes bleeding from. No, i dont, theres blood everywhere. Are you with her now . Yes, oh its in her chest, a big xwash in her chest. And jason woke up to the horror two ways at once, Fire Department alarm, brother alarm. I was asleep as a volunteer firefighter i have a pager, the pager went off, and i could hear casey coming up the stairs, yelling at me, in a panic q theres something wrong with mom. You got to come next door right now. Did you have any sense of what it was . I had no idea what i was going to walk into. What he walked into was a nightmare beyond dreaming. There was his father, in full blown panic and lying on the floor in a puddle of blood was his mother, and the rookie firefighter for an instant to his eternal regret, froze. If i would have come on that situation now, i would have immediately started cpr. There was a great deal of blood, so for somebody to live through that, that much blood, i didnt think it was going to happen. I believe i just missed her last couple of breaths. Minutes later, emts arrived and karen duenas was pronounced dead. The cause, multiple stab wounds, including a massive gash to her chest. Not long after that, the young detective arrived, logan stonehouse, a year under his belt as an investigator, but this would be his first big homicide case as lead detective. And lo and behold i didnt know what i was walking in until i saw a picture on the wall and realized whose house i was in. You knew these people, right . I did. I went to high school with the second oldest son, jacob. And here he found himself looking at the bloody body of jacobs mother, karen. The lady everybody loved, the one who brought cookies to all the games at school. Who could have done this . Detectives were well aware that Violent Crime was up around here, some said significantly, ever since californias overcrowded prisons nearby were forced to reduce populations and had to release some potentially dangerous offenders like drug addicts, possibly desperate for money for a fix. So was this a Home Invasion robbery gone wrong . The detective took a look around the house. He and fellow officers fanned out around the neighborhood. There were some footprints outside the property, right . There was, there was a wood fence that surrounds that piece of the property, and theres a back gate back there and there was a little trail that led out to a canal area. And the first patrolman on the scene told them he had seen a car speeding away, as he raced toward the duenas house. Neighbors reported seeing two strangers nearby that evening. And here in this crime scene video taken the next day, a screen on the window in karens bedroom that looked suspiciously like it had been cut open. Had intruders entered here . Was anything disturbed around the house . No, actually the bedroom was pretty much intact. There wasnt drawers taken open like someone burglarized the place. Also, even though the screen appeared to be cut, didnt look like anybody had actually gone in that way, and so the detective had some questions for the only man known to be in the house all evening, the husband, of course. Mark duenas. What was his story of what happened that night . He told us that he had been up with karen, they were watching a movie, and then once karen went to bed, he tried to stay up a little bit longer to watch the giants game. He was falling asleep during it so he decided to go to sleep himself. Mark, in his room, karen, already down the hall, in hers, the detective took mark to the Major Crimes Unit where mark, who had been awake more than 24 hours by now finished the story himself. Im in my room asleep. What happened . I hear crazy noise, and you know, you hear a cat sound like, it wasnt cat cats. It was a weird was it talking . No, i heard weird screaming type. What did you do . I ran i got up because i didnt want those, whatever it was going on to wake up my wife, because you know, im sensitive like that, and i went to the door by the kitchen, opened it up, and looked out there, i didnt see any cats, shut it, walked down the hallway, looked under the lights were on, so i figure shes up, opened the door and thats when i found her. The detectives questioned mark for more than three hours, had him change so they could keep his shorts and tshirts for testing and then sent him home to hadis children. I remember him coming in the door and just collapsing. Falling on the floor, we we were really worried about him, he kept saying his heart. We thought he was having a heart attack. I mean he was, he was a mess. As the duenas family planned a funeral their big extended family including karens brother joe, and wife jackie, descended on cottonwood. Youve never seen a person more broken. What was your perception of how he took it . He took it incredibly hard. He still does. Along with unbearable grief for the family came anxiety. I lived next door. Im worried for my family. Im putting alarms on every door, because somebodys out there. But the police did not seem to think that. In fact, within a day or two, one of the detectives announced no need to worry about some unknown killer stalking the town. Now why would he say that . Coming up, investigators were about to hear a strange tale from none other than karens husband. Where do babies come from . Well, they come from our hope and a longing to bring something new into the world. Its fitting, then, that classrooms of children are born every day in Northern California the cradle of ideas, changing the very world around us. Every bright spark deserves a hand to help it become something more. And thats why we are here. For our newest neighbors and the people they become. Sutter health. Proudly caring for Northern California, birthplace of pioneers. They measure time in units of pain in little cottonwood, california, during the surreal minutes and hours and days after karen duenas was murdered. The best way i can explain my mom is pure of heart is the best way to say it. The whole big family, karens family, as well as marks, parents, brothers, sisters, gathered to support each other and mourn and struggle with the question that hung in the air, who did this . But the word on the street was there was no question at all. We immediately heard rumors outlandish rumors going, i dont know where youre getting this. The boys heard them, too, rumors the detectives knew the killer was mark, to which the family said thats ridiculous. I know there was no way possible he could have done it. My parents were best friends from as long as i could remember. But if that was true when why would detectives be so suspicious of a man married to his High School Sweetheart for almost 33 years, a man without so much as a traffic ticket on his record, let alone a violent act . Well, its true that when wives are murdered, husbands are frequently implicated, and mark did discover the body, but there was another reason, just minutes after mark sat down to talk to those detectives, he volunteered information that sounded to them like a motive for murder. What was going on in our lives, and it scares me when i think about it. It was an odd little story, one day at work toward the end of 2010, said mark, a u. P. S. Coworker asked him if hed ever gone on facebook. No, said mark, he hadnt. Well, asked the colleague, havent you ever wondered what happened to people you used to know . Facebook might tell you. And mark thought about it and said, well, there was this girl he used to talk to back in high school, wasnt a real girlfriend or anything, but he was curious about whatever happened to her, so sure enough the colleague found the woman on facebook, and pretty soon she and mark were texting and talking on the phone, catching up. We talked and we visited, carried away with a little texting here and there. Carried away . Well, that may be a little strong in this age of sexting and lured electronic dalliances. They talked and texts for several months, even said i love you a time or two, but was it some kind of affair . Well, judge for yourself. Was there ever any pictures sent or anything like that, or was it always just theres pictures that ive just maybe, uhm, me or her, you know, just little innocent, uhm, you know were not into any of that nasty porn, none of that, it was what do you look like now. She had sent a picture of her and she goes your turn. She does a quilt, took a picture of her quilt and showed it to me. Just innocent stuff. She had a picture of her grandkid and stuff like that. And not once did they try to see each other. In fact, when an opportunity came up, they decided no, it wouldnt be fair to their respective spouses of more than three decades or their kids or grandkids, so they didnt, but as mark told the detectives, karen found out what hed been doing when she went through a phone bill, and it hurt her feelings, so he promised to stop, except he didnt. Mark went and bought a secret phone to continue that communication, that karen wasnt aware of. It was the woman who put a stop to it and she sent karen this letter, postmarked just a little less than three months before the murder, asking for forgiveness, promising it would never happen again. Karen told a couple of her kids about it. She was pretty upset for a while. How important was that . Definitely say everything together showed that karen was not happy in their relationship. Mark told them otherwise that it was a happy marriage, the texting thing just a blip but the detectives didnt believe it, so they confronted mark. When did you find out that karen was going to leave you, mark . Leave me . Umhum. She was never going to leave me. Never going to leave you. Honestly. In fact, investigators believed it all backed up what they suspected from that very first night, here, just hours after the murder, when they first accused mark of killing her. I didnt do it, and i, i mean its crazy. Its just like o. J. , we need to be out there finding the real killers, right . Lapd, they didnt have to find the real killers. I know youre doing your job but i would never lay a hand on my wife. I did not hurt her, i did not kill her. I walked in and found her in her condition. Marks family, by the way, said he told them all about that texting relationship. They said didnt seem like such a big deal. It sounds to me that it was just them confiding in each other about their marriages and their families and you know, just an outlet. For youngest son casey it explained the tension between his parents a few months before his mothers murder. There was a good span where they didnt get along but it was a while before. Yes, and they seemed to be back together again . They seemed better than ever. And those claims by investigators about a pending divorce . Not a chance, said the boys. They never were going to give up. They taught us that. Im sure a little bit of trust was lost, you know, someone keeps something from you, but you know, it was something they worked on, and they got over. All that grief infected summer, a cloud darkened over the duenas famil