Revealing mistake: Baby Lily is supposed to be a newborn, but she must be like 4 or 5 months old. When she is supposed to be tucked in a blanket, it's very obvious that they're using a doll that is much smaller than the actual baby.
Continuity mistake: When Bree is talking to Lynette about what Lynette would say to Andrew's lawyer, in the shots facing Bree her right hand is on top of her arm, but from behind, her hand is under her arm. This happens again in the next shots.
Continuity mistake: When Lynette starts talking to Andrew, her car door suddenly goes from closed to open between shots.
Answer: He was investigating the lead not the case.