TOOELE — A man who "admitted he may have taken some bad methamphetamine" was arrested Tuesday after firing several rounds outside a Tooele fitness center, thanks in part to an off-duty officer.

About 4:40 a.m., an off-duty Tooele County sheriff’s deputy had just arrived at Anytime Fitness when he heard multiple gunshots, according to a Tooele County Jail booking affidavit.

Lance Colby Milner, 34, whose last known residence was in West Jordan, was then seen pounding on the back door of the business while holding a gun. A man opened the door to see what was going on, and Milner pointed a gun at him, the affidavit states.

"The victim grabbed the handgun from Lance and ordered him to the ground," according to the affidavit.

The off-duty officer then went into the fitness center and arrested Milner.

Investigators found three shell casings, one live round and a full magazine in the area where the shots were fired, the affidavit states. They also found a nearby fence damaged by gunfire.

"Lance was in possession of the 9 mm Ruger handgun, two knives and a was wearing a tactical AR-15 sling around his chest," according to the affidavit. "Lance was unable to sit still and was talking about unrealistic things. He stated a female popped up in the back seat of his vehicle while he was driving. She was chasing him around and that is who he was shooting at. He admitted he may have taken some bad methamphetamine."

Detectives located Milner’s car in the parking lot and noted that it was so full of items "as if he was living in it. There would be no room for anyone in the back seat of his vehicle," the affidavit states.

Milner was arrested for investigation of disorderly conduct, two counts of criminal mischief, aggravated assault, carrying a weapon while under the influence, possession of a deadly weapon with intent to assault and discharge of a firearm.