"During their interrogation, accused Waqar and Tehsin had disclosed that they had made efforts to make poison with the help of available chemicals such as magnesium sulphate, acetone and castor seeds," the chargesheet said.
"Their purpose behind making poison was to attempt target killing by sending letters soaked with poison. These chemicals have been recovered from Waqar," it said.
These accused have been named in the chargesheet for the offences under various sections of the Indian Penal Code and under the provisions of the Unlawful Activities (Prevention) Act.
In November 2011, the special cell of police had busted the illegal arms factory located in Nangloi area here and arrested several IM suspects.
Tehsin was arrested Mar 25 near Indo-Nepal border in Darjeeling district of West Bengal while Waqas was arrested outside Ajmer Railway Station Mar 22.
Earlier, police had chargesheeted IM chief Yasin Bhatkal, his aide Assadullah Akhtar and others.