An independent investigator should be named to look into allegations that state employees tried to cover up alleged sexual-abuse incidents at a group home near Olympia, a state lawmaker says.

Sen. Pam Roach, R-Auburn, said Wednesday that a current investigation of the OK Boys Ranch by the state attorney general’s office won’t be seen as unbiased, because the office defended state workers against lawsuits filed by former residents of the home.

Fifteen boys who claimed they were sexually and physically abused at the group home won $4.3 million from the state to settle a lawsuit last year.

The Department of Social and Health Services, which oversaw the home, now faces allegations that its employees altered files before giving them to the boys’ lawyers.