trail of what we were doing. >> they even gave lazarus a code name. >> number five. and contrary to police procedure they decided to not tell l.a.p.d. headquarters that their new suspect was a fellow detective. >> you are doing it to protect her or to protect your investigation from her? >> dual purpose. it would protect the integrity of the investigation and if she was not involved, then nobody would ever know about it. >> four cops, knowingly skirted department rules to investigate one of their own. >> it was a difficult phase of our careers. she was one of us. she worked our unit. had worked side-by-side with the people around us. >> but nutall and his three fellow detectives did not waiver. they methodically built a case by exhaustively reviewing the original files and interviewing sherry's friends and family. it became clear to them that stephanie lazarus had the means,