The explosion took place at the Nanaksar Satsang Darbar Gurdwara on Saturday evening as people were celebrating the Indian festival of Baisakhi.
The temple had hosted a wedding earlier in the day and the injured were guests from the marriage party.
“We have set up a commission of inquiry. The protective measures will be extended,” said Police Commissioner Frank Richter.
“We have found no terrorist background… we will work closely with Indian authorities,” Daily Sikh Updates news portal quoted Richter as saying.
According to sources, the temple will remain under police protection for the time being.
A masked person was spotted fleeing the scene shortly after the blast, police said.
Local media reports said three people were arrested on Sunday, but were released after police found them having no links to the incident.
The granthi – male priest – was the most severely injured. There were no latest updates about his condition