An unidentified group has set a fire to the residential area of Shreeram Sugar mill based at Garuda of Rautahat on Friday. A gang of 15-20 people wielding weapons set the residential area of a sugar mill on fire at around 1 am today. The armed gang also set three vehicles and one motorcycle on fire after taking security guards Khil Bahadur Phuyal and Dor Prasad Ghimire under control. The three vehicles with bearing number plate Na 2 cha 6501, Ko 1 Cha 7196 and Ba 10 Cha 5038 and motorcycle, Ba 29 Pa 5723 have been completely damaged in fire. The fire has been doused with the fire engine brought from Gaur, said Police Inspector Santu Lal Jaiswar. Police have launched a manhunt to nab the arsonists.