Bhopal: The lawyer of the eight SIMI under-trials, killed in an encounter by the Madhya Pradesh police, has alleging that their jailbreak hours before they were killed was a set-up and has demanded a CBI investigation.

The lawyer Parvez Alam questioned the police's claim that the prisoners scaled multiple high walls and opened doors at the high security Bhopal Central Jail with keys fashioned out of toothbrushes.

He added the families of the eight men, who belonged to the banned Student Islamic Movement of India or SIMI, will move the Madhya Pradesh High Court seeking a CBI inquiry into their killing by the police, which they allege was "cold-blooded murder".

Madhya Pradesh chief minister Shivraj Singh Chauhan had said it clearly yesterday that the elite National Investigation Agency or NIA will investigate only the jailbreak and not the killing of the prisoners.

That investigation will be conducted by a special team of the Madhya Pradesh police, the state's home minister Bhupinder Singh has said.

Speaking to NDTV, Singh said the eight SIMI men "were planning a huge terror attack" and that a "big network" made their jailbreak possible.

"If such terrorists had managed to escape, it would have been a great threat to national security. The Madhya Pradesh Police managed to trace and kill them in a short time," he said.

Meanwhile, the National Human Rights Commission or NHRC has sought an explanation from the Madhya Pradesh government as well as the state police after some videos seemed to show the prisoners being killed at close range and without any signs of a shootout.

The videos, lawyer Alam said, "show the police and ATS firing. There is no evidence that the accused fired."