I thought DW told LE about his trip to the drycleaners during his interview with them when he was giving him his timeline of activities that day. Only thing is, he only mentioned one trip at first then later it was discovered he actually made 2 drop offs of items to the cleaners that day.
This is the sort of thing that can be easily confused during even honest testimony / interviews.
To wit: In the course of recounting what you did on a particular day, you say, "I went to the dry cleaners." You omit the fact that you went there twice, but that doesn't seem important at the time. You're basically telling the cops what you did that day.