Missouri judge vacates Lamar Johnson's murder conviction

A Missouri judge has ruled to vacate Lamar Johnson's murder conviction. 

Johnson, who has spent nearly 30 years behind bars for a murder 1994 slaying of 25-year-old Marcus Boyd, is expected to be freed Tuesday afternoon.

In 1995, Johnson was convicted of fatally shooting Boyd over a $40 drug debt and received a life sentence. Another suspect, Phil Campbell, pleaded guilty to a reduced charge in exchange for a seven-year prison term.