he s always very positive and very upbeat, very kind. he s a pleasure to work for. reporter: and everyone else police spoke to said the same. gil nunez seemed to have nothing to hide. what s more, after weeks of investigating, there was still no clear cause of death. so all investigators could do was wonder if the love triangle was just an interesting story that had nothing to do with tom s death. but that would all change when the toxicology report came back, and it was a shocker. what had happened to tom kolman. you had never seen it before? this wasn t a common thing. this was now a murder
reporter: investigators wanted answers too. but when the d-n-a results came back, a new question was at the center of the case. that was not only important, that was a showstopper. coming up the new evidence. would it clear gil nunez? it wasn t possible that he would do anything of that nature. when dateline continues. daddy diaper duty. i can t say it s the highlight of fatherhood. but i d rather be here with my little man than not be here because of migraine. i have three words for migraine. i am here. aimovig, a preventive treatment for migraine in adults, reduces the number of monthly migraine days. for some, that number can be cut in half or more. the most common side effects are pain, redness or swelling at the injection site and constipation. talk to your doctor about aimovig. and be there more.
for 13 years. he s always very positive and very upbeat, very kind. he s a pleasure to work for. reporter: and everyone else police spoke to said the same. gil nunez seemed to have nothing to hide. what s more, after weeks of investigating, there was still no clear cause of death. so all investigators could do was wonder if the love triangle was just an interesting story that had nothing to do with tom s death. but that would all change when the toxicology report came back, and it was a shocker. coming up you had never seen it before? this wasn t a common thing.
reporter: what are you thinking when you hear that? well, i m thinking a couple things. i m thinking, that s gonna be a problem at trial because of the contamination. but i m also thinking, thank god, we get a little break. reporter: and after all the additional testing, the medical examiner finally had a cause of death, acute midazolam poisoning. investigators took everything they had to a special prosecutor and argued they were sure gilberto nunez had killed the man he called his best friend. i don t think that nunez was ever a friend to kolman. not for a minute do i believe that. he is a master manipulator. he lives to manipulate. i believe he drew tom in because he wanted to be closer to the wife and have access to the wife. reporter: nearly four years after tom s death, gilberto nunez was indicted for second-degree murder. how did that feel when you got that news? i cried. we all cried pretty hard.