The 71-year-old, who was a member of a shooting club, opened fire during a meeting of property owners in a restaurant attached to a sports club in the town of Dossenheim, Baden-Württemberg.
The state prosecutor said on Wednesday that the pensioner killed an 82-year-old and 54-year-old after accusing the other residents of betraying him over bills.
He then shot himself in the temple.
Among the five people injured was his 70-year-old wife. He reportedly shouted “I will kill you all,” as he stormed into the room firing the pistol, police said.
He had been a member of a shooting club for decades but never came across the police's radar until Tuesday night.
Eight people were in the room when the shooting began. He even followed one of his victims onto the terrace of the restaurant. Police said he fired 17 bullets in total.
Following the shooting, Baden-Württemberg interior minister Reinhold Gall called for large calibre weapons to be banned in the state.