A 60-year-old Sikh priest was seriously injured and two others suffered minor injuries in the explosion.
A third teenager, who was arrested in connection with the bombing of a gurdwara by Islamist terrorists in the German city of Essen, has admitted to the authorities that he was part of a group which carried out the terror attack, according to a media report.
Tolga I, who is known in his circle as 'Amir', appears to be a sort of "commander-in-chief" who has given the order to Mohammed B and Yussuf T to explode a bomb at the Nanaksar Satsangh Sabha Gurudwara on the evening of April 16, 'Report Muenchen' programme of the ARD TV network said.
During interrogation, 17-year-old Tolga did not reveal the background or motive for targeting the Sikh temple, which hosted a wedding ceremony attended by over 200 guests.
He admitted that he was part of a group which carried out the bomb attack on the gurdwara.
Investigators are trying to establish whether Tolga I as well as sixteen-year-old secondary school students Mohammed and Yussuf arrested four days after the attack are part of a terror network or their group included more young people, the report said.
A 60-year-old Sikh priest was seriously injured and two others suffered minor injuries in the explosion, which ripped through the entrance hall of the gurdwara.
Investigators have traced a link of the three men to a radical Muslim clergy and to a travel agency in the city of Duisburg, near Essen, the report said.
The three have also frequently visited the Assalam Mosque in Essen, which is known to the authorities as a meeting place of radical Islamists.
Meanwhile, Germany's federal prosecutor's office is examining the possibility to take over the investigations into the bomb attack from the state prosecutor in Essen on suspicion that the three teenagers arrested are part of a terror network, the report said.
Tolga, who was taken into custody on an arrest warrant issued by the district court in Essen, came to police attention after his mother informed them about his links to radical Islamists and handed them over some notices made by her son, the report said.
She was worried that Tolga was preparing to leave for Syria to fight for the Islamic State (ISIS) terror group.
He is also known to have contacts with the "Lohberger Brigade", in Dinslaken, a group of jihadists who have joined ISIS terrorists as fighters some years ago, according to the report.