The gunman who killed seven people at a Jehovah’s Witness building in Hamburg was a former member of the congregation who police had been warned about, German police have said.

The 35-year-old man, referred to by police as Philip F, left the religious community 18 months ago with “ill feelings”, Hamburg’s head of police Matthias Tresp told a news conference on Friday.

An anonymous letter was sent to police about him in January saying he might be suffering from a mental illness and that he should not be allowed access to weapons.

He is believed to have held a sports shooter licence and felt enraged against religious people, particularly Jehovah’s Witnesses, Mr Tresp said. He had not committed any previous offences, he added.

His apartment was searched by officers who found 15 loaded magazines and four packs of ammunition.

A Koch gun and at least nine empty magazines were found at the scene.

Seven people were shot dead before the attacker turned the gun on himself at around 9pm on Thursday.

Eight others were injured, four of them seriously, out of a congregation of 50.