Despite a state-wide alert sounded by the police after 18 persons, including former CM Babulal Marandi’s son, were gunned down by Naxalites in Giridih district on Friday night, extremist violence continues unabated in Jharkhand.CPI (Maoist) cadres set afire nine trucks carrying bauxite from the Hindustan Aluminium Corporation Ltd’s mines in Gumla on Monday. “They had demanded money. We knew they will strike. But we preferred it rather than succumbing to their demand,” said an HINDALCO official on condition of anonymity.On Sunday, Maoists had gunned down four ‘rebels’ of the Tritya Prastuti Committee, a breakaway faction of the CPI(Maoist), in Latehar. Police said that the Maoists, who had shot dead TPC men, were challenged by the security forces in Lohardaga district. In the ensuing encounter, three Maoists were killed and a bundle of arms was recovered, said Lohardaga SP Subodh Prasad. The police identified the deceased Maoists as Helen Gudia, Joseph Topno and Nukul Yadav who recently came out of jail on bail. Back in Giridih, police have named 10 Maoists in its FIR on Friday killings, but no one has been arrested yet.Meanwhile, five policemen were killed and three seriously injured on Monday after about 200 Naxalites surrounded a police party in Bijapur district of Chhattisgarh and opened indiscriminate firing, said a PTI report from Raipur. Twelve cops were still missing, said sources.