A man in a bathrobe, wielding a stick and a liquor bottle, yelled a police who came to his house early Saturday before getting a gun and firing at an officer, police said in an arrest affidavit.

Dennis Mahan

Dennis Mahan, 61, is accused of aggravated assault on a peace officer, a first-degree felony. Officers went to his house around 2:30 a.m. after a friend told police he was concerned about Mahan based on alarming social media posts.

When police got to the home on Harpers Ferry Lane in South Austin, the front door was open and they could hear yelling, according to the affidavit. Mahan then "emerged from the front door wearing a heavy bath type robe and holding a liquor type bottle in his right hand and a large stick in his left hand," according to the affidavit. Police attempted to give him commands, then attempted to hit him with a Taser, but "it was not effective," they wrote.

After the attempt to stun him, Mahan went back into the house and officers began hearing gunshots from the backyard, the affidavit says.

"A short time later, the suspect opened the garage door, approximately 2-3 feet off of the ground, and fired a shot in the direction of an officer at the scene," the affidavit says. "This officer stated that he heard … ‘buzzing sound’ when the gun was fired. … Officers could hear the suspect yelling and cursing at them."

The police SWAT team responded to the home, broke the front door and deployed "a chemical agent" to force Mahan out of the house, according to the affidavit. He was arrested and taken to South Austin Hospital to be treated for minor injuries, where he is accused of telling both officers and medical staff he would "slice their throats" when his handcuffs were removed.

Mahan was in the Travis County Jail on Sunday, records show, with bail set at $200,000.