The body of forest guard Hoshiyar Singh was found hanging from a tree on June 9.
Alleging that the forest mafia was getting protection from the government, he told reporters here that departmental enquiry or investigations by any state agency would not be sufficient.
"For a fair and impartial enquiry, a CBI probe is a must," he said.
Claiming that forest mafia was active in the state, Dhumal said that the forest officials were feeling threatened and unable to discharge their duties as a result illegal felling of trees was rampant.
The mafia has become so strong that the forest officials are being attacked and beaten, and their mobile phones were being snatched but no action has been taken, which raises doubts about the intentions of the government, the BJP leader said, adding if his party returns to power it would get all these cases investigated and the guilty would be punished.
Dhumal also accused the Congress and the CPI(M) of neglecting Shimla town for last 31 years, saying supply of contaminated water and outbreak of jaundice, which resulted in 32 deaths, was gift of these party to the citizens.