Offices and homes of at least three chartered accountants in the city have been searched in the past seven days after their names allegedly emerged during an investigation into a corruption case against a senior IRS officer in connection with which Govind Agarwal was arrested on Sunday.

The three chartered accountants have been summoned and questioned separately by Calcutta police.

The police are probing allegations against income-tax officer Neeraj Singh who has been suspended.

Singh, a 1994-batch IRS officer, has been facing charges under the Prevention of Corruption Act and penal sections dealing with cheating and criminal conspiracy after alleged evidence emerged from the Mangoe Lane office of his close associate Agarwal in 2016. The case was registered in 2017.

Investigators said a section of certified chartered accountants in the city appeared to have been helping their clients “manage” their unaccounted finances. Leads suggesting their links with several serving and retired central agency officers have led the police to question these chartered accountants, the investigators said.

Agarwal, remanded in judicial custody for a day on Sunday, will be produced in court again on Tuesday.

People familiar with him said Agarwal was a “one-stop-solution” for all accounting services for his clients. His name rarely featured in any official papers.

Agarwal, who lives in south Calcutta, had started out as a junior accountant at a private firm where he had the job of liaising with income-tax officers.

For years, Agarwal operated from a small room on the first floor of a building at 3A Mangoe Lane in central Calcutta. The office neither has a nameplate nor any mention of his company’s name.

On Monday, asked about Agarwal, most people in the building said: “Hum nahi jante (We don’t know about him).”

Agarwal’s lawyer Biplab Goswami said his client had cooperated with the police when he was officially summoned multiple times. “My client is suffering from critical, life-threatening kidney and liver diseases,” Goswami added.

Agarwal’s arrest on Sunday was followed by multiple tweets by Bengal governor Jagdeep Dhankhar who referred to a “politically inspired operation” to target the “CA fraternity”.

Police sources said Agarwal’s arrest was based on “fresh evidence” they had received from the Enforcement Directorate in October in connection with the IRS officer’s case.