christobal melchor and the chapa family or the olgin family. >> reporter: veuleman then showed melchor the letter, and melchor was stunned. >> but he was even more rprised whensaw his picture on the last page of the letter. >>ter: reporhat was because melchor immediately recognized the photo. he knew en and where it was taken. plus, he said, the original photograph was of two people. the missing man, he said, was his former roommate, david strickland. if the snapshot was a surprise to melchor, the name david strickland was an even bigger one for detective veuleman. turns out, he'd crossed paths with david strickland before. >> i'd interviewed david strickland in 2012 just days after the murder. >> reporter: remember that tip about a white car seen speeding from the park the night of the murder? the tipster was david strickland. >> he came in as a good samaritan, wanting to provide information. >> reporter: back then, david strickland lived just blocks from the park where the shootings took place. >> and now here he is being mentioned in connection with a guy who's been mysteriously fingered for the murder. >> that's right. >> so just like that, basically, mr. melchor is no longer the focus of this. it's now david strickland. >> that's right. >> reporter: chris melchor went on to explain that he and strickland were no longer on good terms. melchor believed strickland had