Wheeler was found dead in a landfill on Friday, and the police have trying to retrace his movements between Dec. 28 and then.
On Tuesday, police said a witness had come forward to say that Wheeler had been spotted alive in downtown Wilmington on Thursday afternoon. That is less than 24 hours before his body was found in a Wilmington landfill in refuse that came from trash bins in one of 10 possible locations in Newark, Del.
The case has drawn national attention - Newark police received roughly 70 media calls Tuesday - because Wheeler, 66, lived such a distinguished public life.
A Vietnam veteran who became a driving force behind the controversial memorial on the National Mall, Wheeler worked on nuclear, chemical, and cyber issues at the Pentagon. He was the first chief executive officer of Mothers Against Drunk Driving, a secretary of the Securities and Exchange Commission, and a tireless advocate for veterans.
Wheeler left his office outside Washington on Dec. 28. His body was found in Wilmington on Friday. He was scheduled to take a Amtrak train from Washington to Wilmington on Thursday.
Detectives were able to verify that Wheeler had been seen Thursday near 10th and Orange Streets - close to the Hotel du Pont - but a police spokesman declined to say how this was confirmed. An executive at the nearby DuPont Corp. headquarters, which employs outdoor surveillance cameras, said that the company had "cooperated" with the police but declined to elaborate.
Police say they have no suspects and have released few details about the slaying - in part because they themselves have so many unanswered questions, including where the killing took place.
"We're still trying to [find] the crime scene," said Newark police spokesman Mark A. Farrall. "We're working a lot of leads."
