A reputed gang member who dated a St. Paul police officer pleaded guilty Tuesday to throwing a suspected murder weapon into a creek.

Ramone D. Smaller, 22, pleaded guilty in Ramsey County District Court to aiding an offender by ditching a rifle that police believe was used to kill Leonard Christian Sr. in March 2012.

It's the third time Smaller has been convicted in a violent case. Already serving six years in prison for attempted murder, he was convicted in February for three drive-by shootings in St. Paul in 2013.

While investigating Smaller last year, police learned that he was dating then-St. Paul police Officer Ruby Diaz, now 39. She was convicted of using a friend's identity to wire Smaller money in prison, and was fired.

They began dating in 2013 but broke it off last year.

Smaller testified Tuesday that sometime after Christian was fatally shot in his St. Paul home in the 1000 block of W. Central Avenue, he learned what kind of rifle was used in the crime, retrieved the suspected murder weapon from a van and threw it in a creek.

Assistant Ramsey County Attorney David Miller asked if he did it to protect someone.

"I believe it was an act to defend myself from being a suspect in a murder, because I had it," Smaller said.

Smaller was not asked how he came to possess the rifle. He said he did not know who shot Christian, whom authorities believe might have been killed mistakenly by people looking for his son.

As part of Smaller's plea deal, one count of committing a crime for the benefit of a gang will be dismissed when he is sentenced on May 13, both for disposing of the rifle and for the 2013 shootings. The sentences will run concurrently.

The cases against two men charged in Christian's murder remain pending.

CHAO XIONG