Just before 11:00 a.m. CST,[8] Gregory Paul Ulrich, a 67-year-old man, shot five people at Allina Health's Buffalo Crossroads facility.

[14][12] Police investigators and prosecutors believed Ulrich's motive for the attack was in retaliation for his dissatisfaction with treatment at the clinic, and at the doctors that had stopped prescribing opioid painkiller medication for him.

[7][6] Several warning signs about Ulrich's past behavior and possible motives were not sufficient to prevent the attack from being carried out.

[15][16] At his trial in 2022, Ulrich admitted that he purchased the gun, assembled pipe bombs, and carried out the attack as retaliation against clinic staff.

[19][18] The morning of February 9, 2021, Gregory Paul Ulrich, wearing a large jacket and carrying a brief case, boarded a public shuttle bus at the Super 8 motel in Buffalo, Minnesota.

A clinic staff member, Tamara "Tammy" Schauflerh,[20] greeted the gunman at his arrival and asked Ulrich if he needed help.

Though the bombs did not injure any people, they caused significant damage to the sliding door entrance to the building, shattering several exterior windows, and to the interior area near the desk.

Authorities also recovered his cellphone with a video message where he allegedly alluded to an incident at the clinic, according to court documents later filed charging Ulrich for several crimes.

[31] Gregory Paul Ulrich (born July 19, 1953)[32] a local citizen, was identified as the sole suspect in the attack.

He was known to frequently call the police to make unfounded theft reports or address interpersonal quarrels with people he interacted with.

In a police report filed then, a doctor told investigators that Ulrich had talked about "shooting, blowing things up, and practicing different scenarios of getting revenge".

[34][16] In June 2019, a court services agent wrote that he had just learned that Ulrich had applied for a "permit to purchase" a gun and had yet to be approved.

The agent said that he "highly recommended" that Ulrich be not allowed to acquire a firearm as a condition of his probation for previous criminal offenses.

[16] Despite Ulrich having a restraining order, and an arrest for violation of it, the Buffalo Police Department granted him a permit for the purchase of a handgun.

[37] According to the court documents filed by prosecutors, an investigator believed Ulrich had an addiction to opioid medication, and that it might have been a motivating factor for the attack.

[29] Authorities believed Ulrich was angry at the clinic's physicians from stopping his opioid prescription following a 2016 back surgery and subsequent overdose that required hospitalization.

[15] In particular, news media questioned the Buffalo police department about why it issued a gun permit to Ulrich, which it declined to answer.

[35] Ulrich was confined at a secure state hospital in St. Peter, Minnesota where he awaited trial before the Wright County District Court.

[38] At the request of his defense attorney, the judge overseeing the case ordered Ulrich to undergo an evaluation to determine if he was mentally competent for trial.