COLUMBIA, S.C. (AP) _ Four years ago, South Carolina authorities interrogated Henry Louis Wallace for hours, impounded his car and talked to hundreds of people - and they still couldn't prove he killed a 17-year-old girl.

Now Wallace has confessed to killing Tashanda Bethea of Barnwell in March 1990, Barnwell County Sheriff Joey Zorn said Tuesday.

Wallace was charged Sunday with killing 10 women in North Carolina. He confessed to Bethea's slaying Monday and will be charged with murder in South Carolina, Zorn said.

Margerite Harris, Bethea's aunt, said the family was relieved to know that Wallace had confessed. Bethea, whose parents are dead, had lived with her aunt and uncle for three years, Mrs. Harris said.

Wallace, a Barnwell native, told authorities that Bethea was walking down a Barnwell street when he picked her up on March 18, 1990.

He said he drove Bethea to a remote, wooded area, sexually assaulted her at gunpoint, strangled her, cut her wrists and throat and threw her body in a pond, Zorn said.

When Wallace confessed, ''he was very polite, very intelligent, very humble,'' Zorn said.

When investigators originally questioned Wallace he refused to cooperate.

''He basically had the attitude of 'you haven't got anything on me,''' Zorn said. ''Nobody down here could break him. They gave it their best shot.''