Police are taking this new direction after the only person of interest killed himself last Wednesday and police now think he probably was not involved in the case.
Former prosecutor Robin Sax appeared on "Good Morning America" on Monday and talked about the importance of finding the driver of the Town Car.
"That Town Car is a potential witness that could actually provide some very important clues to what happened at the crash in those moments before and those moments afterwards," said Sax.
Chasen, 64, was shot five times in the chest as she drove home from a party Nov.16.
Detectives are also looking at Chasen's computer records, text messages, her friends and family and her will. Could this be related to money?
"If this was a professional hit, then you can usually trace it back to some sort of financial issue," said attorney Dana Cole.
Robin Sax says there's another question out there: Since Chasen was involved in the art world, could this be an art deal that went wrong?
"The fact that the art world is known for being a little bit dirty, one of trade, and Ronni Chasen's own apartment had many pieces of art that were not her own, but art that was actually on loan, so there are some questions," said Sax. "Was there something that went bad during those dealings?"