German prosecutors have opened a criminal investigation against WBA super middleweight champion Felix Sturm because of doping. Cologne prosecutor Daniel Vollmert says Sturm is suspected of violating Germany's new anti-doping law.

And the 37-year-old could face up to three years in prison if convicted. Sturm tested positive for the anabolic steroid stanozolol after his split decision victory over Fedor Chudinov on February 20 in Oberhausen, Germany.

Sturm won the fight against the previously unbeaten Chudinov on the cards of two judges, while one ruled it a draw. Many fans felt Sturm had been the inferior fighter.

His victory made him the first German to be a world champion five times, having also held theWBA and WBO middleweight titles.

As BoxingScene.com previously reported, the former middleweight and super middleweight world champion Felix Sturm (40-5-3, 18KOs) has left Germany and moved to Bosnia, according to the boxer's manager Roland Bebak.

Sturm was born Germany to Bosnian parents under the real name Adnan Catic. He later changed his name to Felix Sturm.

At age 37 and the doping case hanging over his head, Sturm has no plans to end his career. After recovering from surgery for an elbow injury, he plans to hold at least two fights in 2017.

Sturm has had a rocky career in recent years. After a two round stoppage over Darren Barker to capture the IBF middleweight title in 2013, he was upset in his first defense when he dropped a twelve round decision to Sam Soliman in May of 2014. That prompted a move to super middleweight late that year, and he went to a draw with Robert Stieglitz.

Last May, he fought Chudinov for the vacant WBA 168-pound title and suffered an twelve round split decision loss. There was no controversy over the outcome and even Sturm admitted defeat, but for some reason an immediate rematch was ordered by the sanctioning body - and that led to the February bout which Sturm won. Even stranger, was the fact that his February fight was his first win since the December 2013 Barker bout.