"The Killer Down the Hall," a new "20/20" airing Friday, Oct. 4, on ABC at 9 p.m. E.T ... ex-lover from college. Ruetten told Detective Nuttall that he had already given Lazarus' name to the LAPD ...

RELATED: Early release under consideration for LAPD ex-detective convicted of murder "Today I have learned that I cannot control anyone but myself, and I am responsible for my decisions," she added.

Rojas acknowledged under cross-examination from Deputy District Attorney Dan Akemon that he didn’t touch any other ... rejected for former LAPD detective who killed her ex-lover’s new wife ...