An intruder put a scare into three young children after Butler police say he walked uninvited into their home Friday afternoon, causing them to call for help.

None of the children, between the ages of 11 and 13, knew the man, who also allegedly struck a girl in the buttocks and threatened her. Additionally, he is accused of taking a set of keys.

City officers answered a child's 911 call and arrested Nicholas J. Campbell, 37, inside the house on Fourth Avenue.

Campbell, who has no known address, was arraigned on felony charges of burglary, trespass and terroristic threats. He also was arraigned on misdemeanor charges of theft, receiving stolen property and possession of a small amount of marijuana, and a summary charge of harassment.

He was placed in the Butler County Prison on $50,000 bond following arraignment.

Patrolman Andrew Nierderlander said police were called just before 4:45 p.m. for the report of an unknown man who had entered the home without permission and was still inside.

The 911 caller was a 13-year-old boy who was in the house. Also in the house at the time of the incident was the boy's 12-year-old sister and an 11-year-old girl who was visiting. While the boy called 911, his sister called their mother.

Police got there and found Campbell seated in a desk chair in an upstairs bedroom, Niederlander said. The three children were also at the home.

The officer, in his affidavit, described the children as “visibly upset and scared.”

The youngsters recounted that Campbell had earlier knocked on the front door and then entered the house. Frightened, one of the children ran upstairs to be with the other two youths.

Campbell left but then returned again by way of the front door, police said.

“Campbell was seen taking a set of keys off of the wall,” charging documents said, “and placing them in his pocket to his jacket.”

Campbell subsequently walked upstairs and entered the bedroom where the children were and allegedly “smacked” the younger girl on the buttocks.

“When Campbell did this,” the affidavit said, he made the statement, 'I'm going to (expletive) you up.'”

The older girl told police that she was in fear of being hurt, and ran out of the house.

Police said when they found Campbell, he had suspected marijuana on him. He was arrested without incident.

The mother of the older children arrived home and told police that she did not know Campbell, and he was never permitted to be in her house.

The motive for the incident, police said, was unclear.