A judge agreed to dismiss the second-degree murder convictions of a young Detroit man who pleaded guilty to killing four people at age 14.

Some key events in the lengthy effort to clear Davontae Sanford:

— September 2007: Sanford was 14 when four people were shot in a drug house on Runyon Street in his Detroit neighborhood. Police say he walked up to the scene and made statements that turned him into a suspect.

— March 2008: In the middle of trial, Sanford, 15, pleads guilty to second-degree murder and is sentenced to at least 39 years in prison.

— April 2008: Vincent Smothers, a self-described hit man, is arrested. He confesses to killing 12 people, including the four on Runyon, but is never charged in that case.

— March 2009: Appellate lawyer Kim McGinnis asks a judge to throw out Sanford's conviction after learning about Smothers' confession.

— July 2009: The Wayne County prosecutor's office refuses to back away from Sanford's conviction but acknowledges in court that Smothers may have had a role.

— March 2010: Ira Todd of the Detroit police testifies that Smothers admitted to the Runyon Street killings.

— June 2010: Smothers pleads guilty to second-degree murder in eight other slayings and is sentenced to at least 52 years in prison.

— January 2012: Smothers tells The Associated Press during a prison interview that he's willing to testify on Sanford's behalf. "He's a kid, and I hate for him to do the kind of time they're giving him," Smothers says.

— February 2012: Judge Brian Sullivan says Sanford can't withdraw his guilty plea. He says Smothers' statements don't automatically exonerate Sanford.

— September 2013: A Michigan appeals court overturns Sullivan's decision and sends the case back for more work, including possible testimony by Smothers.

— April 2014: Michigan's Supreme Court decides against Sanford on very technical grounds. The court says the process must start over.

— April 2015: Law schools at the University of Michigan and Northwestern University file a new request to have the murder convictions thrown out.

— May 2015: Prosecutor Kym Worthy asks state police to take a fresh look at the Runyon Street killings.

— June 7, 2016: Judge Sullivan grants a request by Worthy and Sanford's lawyers to throw out the convictions and release Sanford from prison. Worthy says state police found problems with the earlier work and testimony of Detroit police.