An aide to a U.S. congressman has been arrested for allegedly beating a man with a shovel and lunging at him with a kitchen knife during an attack in Baltimore, authorities said.

Police arrested Tim Foster, 32, an aide to Representative Sander Levin, a Michigan Democrat, around 2:30 a.m. on Oct. 8 after an argument with a man identified as his boyfriend escalated into violence, according to Baltimore Police Department arrest records.

Foster is accused of beating and choking the 39-year-old victim and using a kitchen knife and shovel during the attack. The other man is not identified in the report.

At one point, Foster chased the man up a flight of stairs. “When you reach the fifth step, I am going to stab you,” the report quoted Foster as saying. Foster's wife intervened, causing him to drop the knife, the report said.

The victim was hospitalized with abrasions and bruises on his upper back, neck and torso, according to police. The incident was first reported by Roll Call, a newspaper that covers Congress.

Foster has worked for Levin for seven years, a spokeswoman for the congressman said. He was placed on unpaid leave on Friday, she said.

Foster faces assault and weapons charges.

(Reporting by John Clarke; Editing by Ian Simpson and David Alexander)