A convicted cop killer could testify before the grand jury investigating former police officer Drew Peterson.

Anthony "Bindy" Rock, 68, was subpoenaed by the grand jury last week.

Peterson remains a suspect in his 23-year-old wife's disappearance in October. Stacy Peterson was reported missing after she failed to show up at a friend's house.

Rock was involved in an undercover investigation with Peterson in 1985. Peterson was indicted on charges of official misconduct and failure to report a bribe in result of that investigation.

Peterson was fired after the indictment when he was found guilty of those charges. Peterson got his job back after the criminal charges were dropped when two appellate court judges ruled that his dismissal was excessive.

Rock was convicted of the April 1970 murder of Joilet police Det. William Loscheider.

Peterson said he didn't know why Rock would be subpoenaed before the grand jury.

"All he knows is, I tried to buy dope from him a couple times," Peterson said. "I put him away for 20 years. He got out on appeal."

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