Continuity mistake: When Bree is speaking to Lynette on the phone, Lynette asks Bree if she could borrow her scarf to wear at the job interview. But when we see Lynette at the interview, she has no scarf.
Continuity mistake: When Bree and Phyllis are talking about the funeral, the door behind the Reverend changes from open to closed between shots.
Continuity mistake: When Lynette throws the dirty diaper, it hits the glass wall and falls next to the trash can, but when the camera turns to Nina, in the background, the diaper is no longer there.
Continuity mistake: Lynette goes to her second interview and has to take her daughter with her. When she is talking to Stu the receptionist he is eating a long sandwich. In the initial shots the sandwich is whole, but by the final cut away the sandwich has been cut in half lengthways, with the second half now on the desk in front of him.
Answer: He was investigating the lead not the case.