A Minnesota father allegedly used a moose horn and shovel to fatally strike an elderly man he believed was sexually abusing children, according to a criminal complaint.

Levi William Axtell, 27, turned himself in to police Wednesday, minutes after killing a 77-year-old man. Axtell allegedly admitted to the crime, telling detectives that he had known the victim for a long time and «believed that he had sexually abused children in the past,» according to the complaint.

A witness told the Cook County Sheriff’s Office that around 5:00 p.m. Wednesday, a person in a white Dodge Caravan pulled into the driveway of the victim’s Grand Marais home, vandalized a vehicle and he then ran into the residence, the document says.

The witness heard screams coming from inside the house and saw the driver of the truck fleeing from the place.

Authorities said the suspected driver, identified as Axtell, headed to the police station. While he was covered in blood, he walked in with his hands on his head and said that he had murdered the victim, according to the complaint.

The victim was found dead in her home along with a bloody shovel. A preliminary report from a medical examiner said she had defensive wounds to her arms and died from blunt force injuries to the head.

Axtell told detectives that he found a shovel on the victim’s deck and hit the man in the head about 20 times, according to the complaint. She said she «finished him off» by hitting him over the head multiple times with a large elk antler, she says.

Cook County Sheriff Pat Eliasen said Axtell and the victim had «experienced some conflict in the past» and that Axtell had alleged that he had harassed his 22-month-old daughter «but nothing was ever substantiated.»

When asked about the allegations that the victim had molested children, the sheriff said there was apparently a case from the 1970s in Kanabec County, Minnesota. Eliasen had no details about the case, and nothing related to those allegations was found in the victim’s online court records.

NBC News has contacted the Kanabec County Courthouse for comment.

Axtell was charged with second degree murder. Information from the attorney was not immediately available.