As an NSG team reached Amritsar on May 9, DGP Gaurav Yadav said the Punjab Police is taking the help of all agencies to probe the two blasts that took place in the city within 30 hours.
A National Investigation Agency team visited and inspected the site of the second blast on Monday.
The first blast happened on the night of May 6 on Heritage Street, near the Golden Temple. One person was injured and the glass facades of some buildings in the area were damaged in the blast.
The second low-intensity blast on the same street on the morning of May 8 injured one more person.
Punjab Police said it has not found any trigger device or detonator from the area that may have been used.
"We are deeply investigating the Amritsar incident. We have not found any detonator or any such thing. Our forensic team is investigating," Mr. Yadav said.
"We are checking from all angles. if there is any mischief, any terror angle or any personal motive, we will thoroughly investigate," he told reporters in Ludhiana.
Stressing that the Punjab Police was investigating the two blasts, the DGP said they were taking help of all agencies like the National Security Guard. "They [NSG] have specialisation in blast investigation," he said.
"With the cooperation of all these [agencies], we want to find out what happened and what are the facts," Mr. Yadav said.
The DGP, who visited Amritsar on Monday, previously said it appeared the explosive was kept in a container. It was made very crudely and assembled and no shrapnel was used, he said.