Supreme Court won't halt D.C. sniper's execution

Two former wives and a son talk to Larry King about life with John Allen Muhammad tonight at 9 ET.

Washington (CNN) -- The Supreme Court refused Monday to block the execution of John Allen Muhammad, the mastermind of the sniper team that terrified the suburbs of the nation's capital in October 2002.

Known as the D.C. Sniper, Muhammad is scheduled for execution Tuesday evening at a state prison near Jarratt, Virginia.

Muhammad, 48, has continued to profess his innocence during two lengthy trials, including one featuring testimony from young accomplice Lee Boyd Malvo, whom Muhammad referred to as his "son."

With the Supreme Court denying his appeal, Muhammad, 48, is all but sure to die by lethal injection at 9 p.m. ET Tuesday at the Greensville Correctional Center.

The only remaining issue is a clemency petition to Virginia Gov. Tim Kaine, who has indicated that he is not apt to grant it.