Heckler said that a request would be made that, as a condition of bail, Cousin be held until he receives a complete psychiatric evaluation.
On Monday, Cousin said he was investigating an older-model Oldsmobile Cutlass when one of its three occupants fired two shots at him. Cousin said he returned fire three times.
Immediately after Cousin reported the shooting, police set up roadblocks in an effort to find the car.
However, the evidence did not add up, Heckler said.
First, "he literally was not injured," Heckler said.
The vest contained a bullet from a .380-caliber firearm that should have left a welt or bruising at least, he said.
Cousin's three spent .45-caliber casings were found at the scene, but none from a .380 weapon.
Nearby residents were interviewed. One woman who was up reading said she heard "three shots, no more, no less."
Investigators learned that Cousin owned a .380 Ruger. He voluntarily gave it to investigators for testing.
John Finer, a firearms expert from Montgomery County, examined the bullet from the vest and Cousin's gun and determined the bullet "was absolutely fired from his pistol" before the incident, Heckler said.
A law enforcement alert seeking three people in an Oldsmobile was canceled.
Contact Robert Moran at 215-854-5983 or email@example.com, or follow @RobertMoran215 on Twitter.