BERLIN

German authorities were warned about the mental health of the gunman who shot and killed 7 people in Hamburg, police confirmed on Friday.

Hamburg police chief Ralf Martin Meyer said they received an anonymous letter in January, which said Philipp F. could be suffering from mental problems, and suggested that his weapons license should be revoked.

“Our colleagues followed the tip, visited his house to get a clear picture, but at the end of these procedures they did not take a measure, because there had been no legal grounds to prepare a psychological report or to revoke the gun license,” Meyer told a news conference in Hamburg.

Philipp F., a former member of the Jehovah's Witnesses, stormed the religious community’s center on Thursday evening, and killed seven people, including two women and an unborn baby.

The 35-year-old killed himself after police entered the building. He used his legally owned pistol in the shooting, according to the police.

Authorities have not indicated a motive for the attack but said investigations are ongoing.

Hamburg prosecutor Ralf Peter Anders told reporters that there was no indication of a terrorist motive. He said the investigators were currently analyzing his laptops and smartphones to uncover further information.