Gunn stopped his BMW, grabbed a handgun and walked toward the other man’s pickup, according to police. Gunn hit the man in the head with the barrel of the handgun, said Maplewood Detective Mike Gilb. The handgun discharged, and a bullet went through the roof of the victim’s pickup, Gilb said.

The victim drove away, down Hanley Road, and pulled over to hide from Gunn, police said. Gunn got back into his car and chased after the pickup. The pickup driver called police, who arrived and arrested Gunn.

Police say they recovered a 9 mm Smith & Wesson pistol that Gunn had used, as the charges say, “in an angry and threatening manner.”

Gilb said the 64-year-old pickup driver suffered “scrapes on his head from the gun and was obviously distraught.” The man could not be reached for comment.

Gunn, of the 6700 block of Maryellen Street, has not yet been booked on the charges, which were filed Monday. Maplewood police arrested him in February when the incident happened, but he was released pending application for warrants.