Westerfield, 47, was found shot to death in his vehicle around 5:45 a.m. that was parked near 26th and Van Buren, officials said.
He had been on the force for 19 years and was a lifelong Gary resident, police said. Sunday was his birthday, and police said he was engaged to be married.
Police said they have no one in custody, and they are continuing to investigate.
Copyright 2016 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.