A massive manhunt is under way for a man police believe shot and killed a railway police officer on Friday.

The suspect, Zhou Kehua, who is also the suspect in a series of robberies and killings dating to 2004, is thought to have committed his latest homicide when the officer was patrolling a section of railway in Chongqing on Friday afternoon, according to an officer from the Chongqing public security bureau who did not want to be identified.

The attack has intensified the fears that have been stoked by the 42-year-old gunman's alleged crimes. He is believed to target people who are withdrawing money from banks and has become adept at dodging police manhunts.