As per sources, it has been found during the investigation that HE 36 series hand grenade has been used in the attack; a grenade which usually used in Pakistan.
The incident took place inside the Nirankari Bhavan's prayer hall at Adliwal village near Amritsar's Rajasansi, police said. A congregation of the Nirankari followers was being held inside at the time.
The Sant Nirankari Mission is a spiritual organisation and the Bhavan here is located close to the international airport and Indo-Pak border.
The grenade was lobbed by one of the two people who had their faces covered. One person pointed a gun at the volunteers manning the gate, while the other one hurled the bomb after which they escaped, police and eyewitnesses said.
An FIR was registered based on the statement of Nirnakari sect volunteer Gagan, who was on duty at the main door of the premises.
Inspector General of Police (Amritsar Border range) SPS Parmar, who visited the spot, said about 200 devotees, including women, were inside at the time of the incident.
They had gathered for the congregation held each Sunday. No CCTV was installed at the premises, preliminary probe found, he said.
SSP (Rural) Parampal Singh said two armed masked persons forced their way inside by pointing a gun at Arjan and Gagan, who were on duty at the gate. "After they gained entry, one of them threw a grenade-like object at the congregation and escaped," he said, adding a hunt is on to nab the accused.