Two police constables who were allegedly trying to extort money from a man, who had helped the police in nabbing four persons involved in the theft of his own delivery van, have been arrested. The accused constables, identified as Yashpal and Rajpal, were posted at the Kirti Nagar police station. They were arrested on Friday under provisions of Prevention of Corruption Act, DCP (Vigilance) R K Jha said on Saturday. “The owner of a delivery van approached the Vigilance Branch and complained that the constables were demanding Rs 20,000 for the release of his van which was confiscated by the police following the arrest of four thieves who were arrested by the help of the van driver (complainant),” Jha said.