WATERVILLE — A Waterville man is accused of breaking into the home of a 73-year-old woman early Sunday morning and sexually assaulting her at gunpoint, police said.

Waterville detectives arrested Mark Daniel Halle, 32, of 53 Victoria Drive, at 10 p.m. Sunday following a daylong investigation.

Halle is charged with felony counts of gross sexual assault, burglary and aggravated assault and also assault and criminal threatening. He is being held at the Kennebec County Jail in Augusta on $225,000 cash bail.

Officers were called to a home off West River Road at 5 a.m. Sunday by a woman who said she had been attacked in her home, Massey said.

The woman told police that shortly before 5 a.m. she was woken up by a loud bang. When she went to check it out, she was confronted by a man dressed in a hooded sweatshirt and armed with a handgun. The man forced her back into the bedroom and put a pillowcase over her head before sexually assaulting her. He then severely beat her shoulders and head with the gun, Massey said. The woman suffered multiple bruises and was later hospitalized, he said.

After the attack, the man demanded the woman take a shower and threatened to kill her if she called the police, Massey said.

The brutality of the apparently random attack was shocking and disturbing, Massey said.

“You think that after a lot in law enforcement nothing would shock you,” Massey said, “but this was such a vicious attack it goes to show that there are monsters living amongst us who are willing to commit such violent crimes on victims that are innocent and defenseless. and then feel no remorse.”

By tracking footprints in the snow, and with assistance from a Maine State Police tracking dog and handler, detectives found a set of keys, and then a gun that had been stashed behind a small shed at a nearby property, Massey said. The weapon was a pellet gun that looked like a real firearm, he said.

“I’m sure in her mind there was no question it was a real gun.” Massey said.

Investigators eventually followed the trail to the residence on Victoria Drive where Halle was staying with his sister, Massey said.

Halle’s sister, who was home when police interviewed him, said the set of keys were the same she had given him.

Halle was later questioned by police at the Waterville Police Station, where he admitted to the break-in and assault and said he had brought wire to tie up the woman up, Massey said.

Investigators do not know a motive for the attack. Massey said Halle does not have a criminal history in Maine, but had only been living at the Victoria Drive address for a year and had moved around a lot among various states.

Despite her injuries and trauma, the victim called police Sunday afternoon and thanked them, Massey said. She is being helped by family members and is getting support from agencies that deal with victims of sexual assault, Massey added.

“It is amazing how she is holding together psychologically,” he said. “She is just going to need a lot of support in the coming days from everyone.”