Continuity mistake: When Julie is leaving we see that she leaves the door open and then it closes with a slight open gap, yet just for one shot the door is completely closed, then it's open again. (00:09:50)
Continuity mistake: When Lynette gives her husband his photo, the position of the photo changes in between shots. (00:13:05)
Continuity mistake: When Gabrielle and Carlos are saying hello to Ashley, the position of her hands change on the ball, from the front to the side to the front again. (00:14:40)
Continuity mistake: When Karl is speaking to Susan whilst she's in the towel, we see in one shot his chin is resting on his palm, then when the shot changes he tilts his head and then moves his fingers to his chin then when the shot changes his chin is resting on his palm again. (00:25:00)
Continuity mistake: When Bree steals Mary Alice's tape in Dr Goldstein's room, she takes it with her right hand and grabs it to her waist while she raises her left hand to her hair. In the next shot when the doctor enters the room, you can see her right hand is up, and when the camera comes on her the next shot, her left hand is up again.
Answer: He was investigating the lead not the case.