Around two weeks ago, Hammad Adil was arrested in a raid, along with Muhammad Tanveer, an alleged Tehrik-e-Taliban Pakistan ringleader.
They were caught with the help from intelligence agencies from their hideout in Phulgran in Islamabad's suburbs and a car laden with explosives was also seized from their possession, media reports said on Tuesday.
These two were suspected of planning the attack on Bhatti with the help of another accomplice Omer Abdullah.
"They waited for the former minister in a car outside his residence and opened fire," said a police official.
Adil was among the planners while Tanveer provided him with the AK-47 and other weapons used in the assassination.
In March 2011, Bhatti was gunned down in the national capital.
During the interrogation, Adil told the police that he planned to murder Bhatti as he had spoken about amending the blasphemy laws and supported 'blasphemers', The Express Tribune reported.
Meanwhile, he also reportedly told the police that he was preparing for another terror attack on a major installation.
A suicide bomber was on his way from the tribal areas to Islamabad to drive and hit the explosives-laden vehicle (found during the raid) into a key target in the capital city, the report said.
Image: Slain Pakistan minister Shahbaz Bhatti