One of the victims in Tuesday's mass shooting at the Allina Health clinic in Buffalo, Minnesota, has died of their injuries.

Hennepin Healthcare has confirmed that the patient who was brought to HCMC in Minneapolis following the Tuesday morning shooting succumbed to their injuries.

No details about the victim have been released.

Three others are in a critical but stable condition at North Memorial Hospital, with another victim having already been discharged from the same hospital.

A 67-year-old man, Gregory Ulrich, has been arrested in connection with the shooting.

Police on Tuesday said that they believed he was targeting the clinic specifically. It has since emerged that he had previously made threats about a mass shooting and blowing up a hospital as he became angered about treatment for chronic back issues.

Buffalo police reports, cited by the Star Tribune, notes that he threatened four Allina facilities, with "Buffalo first on the list."

Allina filed a restraining order against Ulrich and he showed up at the Buffalo clinic in spite of this, but charges for violating the order were dismissed as Ulrich was found not to be mentally competent to stand trial.

Police also found suspicious devices both in the Allina clinic lobby on Tuesday and at a Super 8 Motel room, where Ulrich was staying.

Related: Police identify suspect in Allina Clinic shooting as 67-year-old