Mary-Kate Olsen, the former child star of Full House, stated today that she will only accept to be interviewed by the Drug Enforcement Administration (DEA) about Heath Ledger if she is shieled from possible prosecution for any charges related to his death. The drug agency is trying to find the source of the prescription drugs that caused Ledger's overdose on Jan 22. Olsen, who has been dating Ledger in the months before his death, has been named a prime suspect.