A staff member at the Minnesota Sex Offender Program (MSOP) in Moose Lake was seriously injured after an “unprovoked attack” by a client Monday, local outlets report.

The 53-year-old victim was doing his rounds when a client hit him from behind with something heavy, Northern News Now reported, citing spokespeople from the program. The client then allegedly began kicking and beating the staff member until other staff managed to intervene.

“The client approached him from behind and struck him in the head with a heavy object. After the staff member collapsed, the client continued beating and kicking him in the head as other staff members rushed to his aid,” Minnesota’s Department of Human Services said in a statement cited by MPRnews.

A staff member is in the hospital after an attack at the Minnesota Sex Offender Program facility in Moose Lake Monday afternoon. | https://t.co/6rhIFX25ub pic.twitter.com/F7wl71wSjE

— WCCO | CBS News Minnesota (@WCCO) May 2, 2023

Law enforcement from the Carlton County Sheriff’s Office were called to the scene at around 1:30 p.m., Northern News Now reported. The victim was transferred to a local hospital via helicopter, where he remains in unknown condition, according to the outlet. (RELATED: ‘A Parent’s Worst Nightmare’: Police Find Seven Dead Bodies On Property Of Convicted Rapist)

Authorities arrested the alleged attacker and identified him as 29-year-old Nicolas Aron-Jones, Northern News Now reported. He was brought to Clark County Jail and will likely be charged with assault, according to KEYC.

“We are deeply disturbed by such a brutal, senseless attack. I’m grateful to those who tried to intervene and protect our coworker,” MSOP Executive Director Nancy Johnston said in a statement cited by the outlet. “Our hearts are with him and his family, and we’ll be there to support him as he recovers.”