A 56-year-old man imprisoned for nearly three decades for a 1982 rape and murder walked free after a judge ruled that St. Louis police hid or destroyed evidence that cast doubt on his guilt.

George Allen Jr. served 29 years of a 95-year sentence in the February 1982 death of 31-year-old Mary Bell. She was attacked and killed in her St. Louis apartment during a blinding snowstorm.

A Cole County judge overturned Allen's conviction Nov. 2. Circuit Judge Dan Green told Allen Wednesday he could return home while the state appeals that ruling.

The case took a turn two years ago after lawyers found previously undisclosed documents showing police did not tell prosecutors or defense attorneys they evidence that Bell's attacker had a blood type inconsistent with Allen's.