The attacker who had taken 18 hostages in a German cinema was a Mannheim-born German national, prosecutors said on Friday.
The teenager entered the Viernheim theater on Thursday afternoon wearing a balaclava and boots popular with German neo-Nazis. He also carried what appeared to be a gun, a rifle and a several hand grenades.
The attacker then barricaded himself inside the cinema, taking four workers and 14 visitors hostage. He was later shot dead when special police breached the room.
On Friday, officials said they had no indications of political or terrorist links and that the man's motive remained unknown.
The attacker's weapons turned out to be air gun replicas made to look like real firearms, prosecutors said. The investigators found no live ammunition at the scene and the alleged hand grenades also turned out to be fake.
None of the hostages, who also included children, was hurt in the incident.
Sources within Germany's security forces have claimed the man acted alone and probably had mental issues.
The Viernheim cinema multiplex is located some 10 kilometers (6.2 miles) from the suspect's native city of Mannheim in southwest Germany. However, the would-be gunman had been living in the north of the country ahead of the attack.
Gas pistols and other less-than-lethal weapons have become increasingly popular in Germany, where strict gun control laws limit people's access to deadly firearms. Gas cartridge guns can produce a loud noise when fired, similar to a conventional gunshot, but the projectiles are generally not powerful enough to inflict permanent injury.