The suspect in a shooting at a Minnesota health clinic that left one person dead and three other people critically injured Tuesday is alleged to have threatened to attack medical facilities in 2018, according to police records.
In October 2018, the man, Gregory Paul Ulrich, called his doctor three times and made threats involving "shooting, blowing things up, and practicing different scenarios of how to get revenge" against four Allina Health medical facilities, according to a report by the Buffalo Police Department.
Among the facilities he is alleged to have threatened was the Allina Health Clinic in Buffalo — the urgent care facility where Tuesday's shooting took place.
At the time, the doctor told police that Ulrich said he would not act on his threats, but he said he believed "Mr. Ulrich is a high threat to society and himself."
Ulrich's younger brother, Richard Ulrich, said Wednesday that the alleged threats were "related to opioid pain medication."
Richard Ulrich, 63, of Florida, said his brother became dependent on opioids when he had back surgery two years ago.
"They discontinued it after a few weeks, and he was upset that the doctors wouldn't give him more," he said. "He seemed like he was frustrated and mad with the doctors."

According to the report, Ulrich was taken to an emergency room for a mental health evaluation after he was accused of making the threats. Shortly after, Allina Health staff members filed for a restraining order against Ulrich, records show.
Ulrich was arrested on a charge of violating the harassment restraining order in November 2018, according to the report. A month later, he was given a notice of trespass from a Stellis Health clinic in Buffalo, the report said.
The charge was dismissed last year after Ulrich was found mentally incompetent, records show.
The shooting Tuesday occurred at about 11 a.m. at 755 Crossroads Campus Dr. in Buffalo, police said. Officers, Wright County sheriff's deputies and SWAT teams responded to a report of gunfire at the Allina Health Clinic.
Minnesota Gov. Tim Walz said in a news conference Tuesday that "some improvised explosive devices" were found.
Wright County Sheriff Sean Deringer said Tuesday that the Minneapolis police bomb squad was investigating a suspicious package. Police said the bomb squad also investigated a Super 8 motel where Ulrich was staying.
"We did send a team from my office over there to evacuate the Super 8 motel," Deringer said. "We did find additional suspicious devices at the Super 8 motel. It's been evacuated. We cleared the area."
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Five people were transported to hospitals, said Kelly Spratt, president of Buffalo Hospital Allina Health. Four patients were taken to North Memorial Health, where three were stable in critical condition, the hospital said. The fourth patient was discharged.
The fifth person, who was taken to Hennepin County Medical Center in Minneapolis, died later, the hospital confirmed Tuesday.
Ulrich had a number of previous charges against him in Wright County and in neighboring Pine County dating as far back as 2004, most of them related to drug and alcohol offenses. He was most recently convicted in 2014 of possession of marijuana, court records show.
Ulrich is expected in court Thursday at 10:30 a.m., the Wright County Attorney's Office said.