JAMSHEDPUR, India, March 5 (Reuters) - Supporters of an Indian member of parliament shot dead by suspected Maoist rebels blocked roads, damaged dozens of vehicles and uprooted power pylons in a strike on Monday to protest his killing. Many businesses, schools and transport services were closed during the 12-hour strike in the eastern state of Jharkhand where Sunil Kumar Mahato was shot dead on Sunday during a visit to a village. The assailants killed three others, including two of Mahato's bodyguards and a worker of his Jharkhand Mukti Morcha party in an attack that analysts said could mark a switch in strategy to more high-profile assassinations by the Maoists. At least four trains were stopped on the tracks by angry protesters near the railway station at Giridih, 90 km (55 miles) northeast of the state capital Ranchi. The state's deputy chief minister, Sudhir Mahato, said all efforts were being made to find the killers. "We are in hot pursuit of the killers who seem to be Maoist rebels as they were seen shouting pro-Maoist slogans immediately after the killing," Mahato said, adding the slain deputy had been facing threats from the Maoists. Jharkhand is one of India's 13 states affected by the Maoist revolt which began in the late 1960s. Thousands of people have died in the conflict. The rebels say they are fighting for the rights of poor farmers and landless labourers and attack security forces, government officials, politicians and state property. "The Maoists have changed their war tactics and will be targeting high-profile politicians more often," B.K. Ponwar of the Counter-Terrorism and Jungle Warfare College in the neighbouring state of Chhattisgarh, also a Maoist hub, said. (Additional reporting by Sujeet Kumar in Raipur)