The arrest of a suspected henchman of MLC Ritlal Yadav from a commercial complex on Sunday morning has pointed police towards gangs extorting railway contractors and a possible nexus between the criminals and government officials.

Ajit Kumar Singh was arrested from Kulhariya Complex under the jurisdiction of Pirbahore police station. Singh had gone to the market complex - which also houses a railway office - with some of his associates to extort railway contractors. A police team was waiting at the complex in civil clothes to nab the men.

"The police had received a tip-off that the gang working under Ritlal's directions had assembled at the market complex. The tender of a railway project was to be opened at the office and railway contractors had assembled there," said Patna senior superintendent of police (SSP) Manu Maharaaj. "The police team present at the spot nabbed Singh and his men the moment they started to threaten the contractors into paying them extortion."

Maharaaj added that Singh confessed to working for Ritlal, an Independent MLC lodged in Beur Central Jail with several cases lodged against him, during interrogations.

"The gang would target contractors who bagged railway work and take 10 per cent of the project amount from them. We have come to know that some railway officials are also involved and they provide the gang information," said the SSP.

Apart from Ritlal's men, other gangs at work have got the police on their toes.

SSP Maharaaj added that there are several gangs demanding extortion from contractors of different state and central government departments. "The police have identified these gangs and are planning an operation to contain them," he said.

One of such gangs is the Sambhu-Mantu group that mostly targets central public works department (CPWD) contractors.

"These men have been a headache for the cops," a police officer said. "In October 2011, the gang shot dead a Grade V CPWD contractor in the Punaichak office. The accused were arrested after a long investigation but they are now out on bail."

While the established extortionists are already operating, the small fish are also trying to squeeze in.

"A Rintu Sharma gang is targeting irrigation department contractors. While there are criminals looting and killing people, these extortion gangs are more organised and know a better way to earn big bucks," a senior officer said. "The police are trying to hit them from all possible angles."