but what about that old flame joe giarusso? without a doubt, in lynn's apartment just hours before she was killed. the neighbors had seen him there eating dinner. >> reporter: joe told the detectives lynne was fine when he left about midnight. >> reporter: didn't that make you think that he might be a suspect? >> oh, yeah. he was, of course, somebody we had to investigate immediately. >> reporter: so they took joe in for questioning. he, too, seemed very forthcoming. and if he wasn't deeply upset about what happened to lynne he was putting on a good act. still, the detectives noticed something strange on his fingers --several cuts. he insisted they happened at work, in a lab where he dropped a test tube. he would never hurt lynne, he told them. had no reason for jealous rage. >> he was in a relationship with another woman. and was still visiting our victim, and apparently were friends. >> reporter: by the time lynne was murdered, said joe, he was in bed with his girlfriend. what to make of the story? until his alibi could be che