A Portland man punched another man and then pointed a shotgun at bystanders after they tried to keep him from driving while impaired, police said Thursday.

The incident happened about 1 a.m. Wednesday near Samuel’s Bar & Grill on Forest Avenue.

Portland police arrested Zachary Bowman, 41, and charged him with assault and criminal threatening with a dangerous weapon. A  spokesman for Portland police said Bowman was “extremely intoxicated” and at the bar until closing time.

Witnesses told officers that Bowman became angry when bystanders tried to prevent him from driving while impaired. After punching one person, Bowman retrieved a shotgun from his car, racked the weapon several times and pointed it at a group of bystanders, police said.

He was arrested at the scene, the police spokesman said.

Bowman was being held on $5,000 bail at the Cumberland County Jail on Thursday night. Jail officials said they could not put through a reporter’s request to speak to Bowman until Friday morning.

Anyone who witnessed the incident is asked to call Portland police at 207-874-8575 or call the anonymous tip line at 207-874-8584.