The assistant inspector who fired at Mumbai hostage-taker Rohit Arya took the call since children were involved and the situation presented a "real threat", an official said on Friday.

Arya was killed on Thursday in a police operation mounted to free 17 children and two women, including a senior citizen, he had taken hostage inside R A Studio in Powai.

Arya was shot by Powai police station API Amol Waghmare, the official said.

"Waghmare had tried to speak to Arya urging him not to take any extreme step. But Arya pointed his gun at the officer and it was a real threat. In self defence, Waghmare fired at Arya, who, unfortunately, succumbed later. Waghmare and a constable were inside the first floor of the studio where the incident occurred. The constable was standing behind," the official said.

"In his complaint, he (Waghmare) has told police Arya pointed his gun at him and there were children around. Considering the situation presented a real threat, he opened fire. It has also come to light in the preliminary probe that there was some plan in his (Arya's) mind for a few months," the official added.

The official said the Crime Branch, which is probing the case, has collected the gun that was in Arya's hand.

"It is being sent to the Forensic Science Laboratory for analysis. It will also determine if firing took place from Arya's gun. All other evidence from the spot has been collected. It includes a foul smelling cloth. It needs to be verified if Arya poured some chemical on it to set it on fire," the official said.

The probe team is verifying information by speaking with persons involved in the project, he added.

Arya, originally from Anand in Gujarat, was staying in Pune and had shifted to Mumbai two months ago, he said.

"He is survived by his wife and 10-year-old son. His wife was in Ahmedabad at the time of the incident. Due to kin not being available in Mumbai, Arya's body was kept at state-run J J Hospital. Post mortem was carried out in the evening after his brother-in-law and other family members reached the hospital," the official said.

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