Berlin: A teenager arrested for his alleged involvement in a terror strike at a gurudwara in the German city of Essen ten days ago was a 'repeated offender', police has said.

The 16-year-old youth was also arrested for an attempted burglary at a shop in the city a day before the attack, a police spokesman told PTI.

"As usual in the case of teenagers getting involved in petty crimes, police set him free after interrogation, registering his personal details and initiating a criminal case against him," the spokesman said.

Police are now investigating whether the terror suspect, identified as Mohammed B and his 16-year-old accomplice Yusuf T had any links to the Salafists or other radical Islamist groups.

The duo are suspected of planting a bomb hidden in a backpack, in the entrance hall of the Nanaksar Satsangh Sabha Gurdwara. The bomb exploded at the end of a wedding ceremony on April 16, injuring three persons, one of them seriously.

Investigations are also focusing on how they got the instructions and the material to make a bomb, the spokesman said. Police traced the two men after CCTV footage showed one them carrying a backpack with the logo "Russel Athletic".

Investigators found the remains of a similar backpack in the debris of the explosion. They were apprehended in Essen and in the neighbouring
town of Gelsenkirchen early last week. The two suspects are currently in a preventive custody. Local media reports said Mohammed B is known to police as a "repeated offender".