Manuel Charr resumed training in the hospital after being shot in the stomach earlier this month.
The German heavyweight needed emergency surgery but is recovering well. He even posted a video on Facebook of him training in the hospital.
And on Monday it was reported that the main suspect in the shooting incident had given himself up to police in Essen.
Two daily newspapers, Bild and Die Welt, reported that the alleged gunman had walked into a police station with his lawyer. The police had been looking for him for 12 days and an arrest warrant had been issued.
It seems Charr and the suspect knew each other and the boxer identified the man.
The 30-year-old Charr, who lost a one-sided heavyweight title fight against former champion Vitali Klitscho in 2012, was shot in the stomach after a late-night argument in a kebab snack bar in Essen on September 2.
Charr, nicknamed "Diamond Boy" and of of German-Lebanese origin, also lost his most recent bout when he was knocked out in a clash with Latvia's Mairis Briedis in Moscow in August. In May he beat Australian Alex Leapai on points.
In August 2006, he was involved in a knife fight after throwing raw eggs at passers-by on a busy street in Berlin. He faced charges of attempted murder, but was acquitted because of a lack of evidence.
He has a professional record of 28 wins in 32 fights, including 16 knockouts. Three of his four defeats were inside the distance.
No arrangements have been made for his next fight.