Ralf Martin, chief of Hamburg Police said Phillip was understood to be “enraged against religious people, particularly Jehovah’s witnesses”. He left the congregation around 18 months ago but there were reportedly “ill feelings” since 2014.
The shooter, whose backpack contained massive amounts of ammunition, was known to have a license for a legal, sports pistol. Police had performed a surprise check-up on Phillip last month but they found nothing suspicious, police said.
In the footage, taken from a distance, Phillip appears to walk up to a window and open fire into the building before storming inside.
Police, who were called at 21.15 local time on Thursday, said the suspect was found dead at the scene.
Nine empty magazines, which carry up to 15 bullets, were found at the scene.