A sex offender housed at Minnesota’s state treatment facility in Moose Lake has been charged with attempted murder after allegedly using a makeshift knife to slash the throat of a staff member there.

George Mack Jr., 42, was charged Tuesday with first-degree attempted murder and fourth-degree assault of secure treatment facility personnel, both felonies.

The assault left a clinician at the Minnesota Sex Offender Program (MSOP) with two gashes to his throat, while a staff member who intervened also suffered injuries, according to the criminal complaint. Mack is being held in the Carlton County jail in lieu of $500,000 bail.

“This assault had the potential to cause extraordinary harm,” Tony Lourey, commissioner of the state Department of Human Services, which oversees the MSOP, said in a statement. “I am relieved that the injuries to staff, while serious, were not more severe. I am very proud of those who stepped in to protect their co-worker and subdue the attacker.”

According to video footage of the incident, Mack lunged at a clinician who was leading a community meeting in an open area of the MSOP facility. Mack grabbed the clinician from behind and made at least two slashing motions across the front of his throat, the criminal complaint says. The clinician was able to avoid further injury by jumping out of his chair and running from Mack, the complaint says.

Another employee intercepted Mack, sustaining several blows to his head and ribs. Mack was then subdued by several staff members.

In an interview with police, Mack said he made a makeshift weapon with a razor blade fastened to a toothbrush with dental floss and rubber bands, records show. The victim said that while Mack was slicing his throat, he said, “I’m in charge here” and “You’re my bitch.” Mack then chased after the clinician, shouting, “I’m the boss.”

“[The victim] was visibly shaken,” the complaint says.

This is the second time since 2014 that Mack has been charged with assaulting a staff member at the MSOP facility. Mack also has three convictions for criminal sexual assault between 1996 and 1998, according to state court records.