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 as he wasn’t seeking medical help.

He held a sports shooter licence and was reported to have felt enraged against religious people, particularly Jehovah’s Witnesses, and his former employer, Mr Tresp said.

Mr F was not married, had been living in Hamburg since 2014 and studied in Munich before that.

In response to the letter, on 7 February two officers searched his flat unannounced and found his semi-automatic pistol securely stored in safe.

They saw no evidence of mental illness so did not ask for a health assessment, the authorities said.

He was described then as being “cooperative” and “happy to give information”.

The suspect had reported crimes, including fraud, but had no criminal history himself and was not otherwise known to police, they added.

Found dead with gun beside him

Mr F was found dead with the same Koch gun next to him inside the Jehovah’s Witness building in the Gross Borstel district just after 9pm on Thursday.

He shot 10 times at a woman inside her car in the car park outside, but she escaped. Twenty others fled the scene unharmed.

The suspect entered the building after shooting at a window and breaking through it before running to a worship hall on the first floor.

Seven people, including an unborn baby, were shot dead there before he turned the gun on himself.

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

At around 12.30am on Friday, police searched his flat for a second time where they found 15 magazines, 200 rounds of ammunition, laptops and smartphones.

He was found with nine empty magazines, two in his hand and 20 loaded ones in his backpack.

His motive for the attack is not yet clear, but authorities have ruled out anything political, the head of police told the news conference.