The alleged kingpin of a kidnapping ring was arrested from a check-in counter at the airport on Wednesday afternoon just as he was about to flee to Jaipur.

“The accused, Sadab Siddique, was wanted in connection with a kidnapping case and was apprehended by CID (Criminal Investigation Department) officers,” said an airport official. “Siddique was due to board an IndiGo flight to Jaipur at 2.20pm,” he added.

The sleuths had taken Siddique’s associate Khalid Khan — arrested on Tuesday in connection with the case — clad in a burqa, to the airport to identify the kingpin.

According to CID officials, Siddique had masterminded the abduction of coal trader Sriram Bochasia on March 8.

Siddique had become a drinking partner of Bochasia, 48, a resident of Shibpur in Howrah. On March 8, Siddique asked Bochasia to meet him in front of City Centre. Bochasia left home around 6.30pm on a motorcycle, and was not seen again by his family till March 19.

“Siddique along with Khan and two other associates had picked him up in a Honda City and held him captive in a hideout in North 24-Parganas,” said Rajeev Kumar, the special inspector general (operations) of CID. They had forced him to call home to say he was on his way to Ranigunj for work.

On March 9, Bochasia’s wife Bela received the first ransom call demanding Rs 1.5 crore. Bochasia’s brother Sarod alerted the police, and the case was taken up by CID.

Negotiations continued between the kidnappers and Bochasia’s family, and the ransom amount was scaled down to Rs 40 lakh. “Bela and some other relatives delivered the money after a 40-minute ride on a suburban train from Howrah,” Kumar said. But the kidnappers demanded more money which was not forthcoming. Bochasia was finally dropped off on Bally Bridge around 4.30am on Tuesday.

Asansol police, tipped off by the CID, picked up Khan on Tuesday. During interrogation, he revealed that Siddique was the mastermind and he was planning to leave for Jaipur.

This prompted the sleuths to plot the airport operation on Wednesday.

“We are looking for the other two kidnappers and the ransom amount,” Kumar said.