CLEVELAND, Tenn. (AP) _ A man apparently stabbed his son and daughter to death because he wanted to ``pay back mom,'' then was shot and killed by a sheriff's deputy.

Tracy Thacker, 39, had removed the 5-year-old boy and 9-year-old girl from school on Tuesday morning, writing on a sign-out sheet that he was taking them ``to pay back mom.''

The retired Marine and his wife, Holli, were separated and planning to divorce, authorities said. She was not home when the deaths occurred.

Bradley County sheriff's spokesman Chip Bryant said Thacker apparently told an 18-year-old stepdaughter that she ``better get out'' of the house. Authorities believe the children were still alive when the teen-ager ran for help.

Deputies had arrested Thacker, a civilian recruiter for the Marines, in May on a domestic violence charge. According to a police report, he tried to break his wife's neck when she refused to have sex with him. Authorities went to the house again on a domestic violence call on Oct. 1, but Bryant didn't have specifics.

Holli Thacker was staying with friends and could not be reached for comment.

Bryant said Thacker's stepdaughter, his wife's daughter from a previous marriage, called police from a neighbor's house. When deputies arrived, Thacker held them at bay at the front door and threatened to commit suicide. They smelled smoke from a fire he apparently set.

Thacker then moved to a side door and, holding a bloody knife, confronted a deputy.

``I heard someone yell, ``What do you think you're doing here?' and then two gun shots,'' said neighbor Dean Johnson.

Authorities said the deputy fired at least one shot, killing Thacker.

Firefighters put out the blaze and found the bodies of the children, Carson and Maylyn.

Maylyn was stabbed 15 times in the torso and Carson was stabbed three times in the chest, according to an autopsy report released Wednesday.

``It was just a violent rain of knife blows,'' Bradley County medical examiner Ron Toolsie said.

Thacker had the legal right to take his children from school, and his note on the sign-out log was noticed too late, said Bradley County schools Superintendent Bob Taylor.