The CBI on Sunday arrested Samir Sheikh, the father-in-law of Lalon Sheikh who is the prime suspect in the March 21 Bogtui carnage case in Birbhum district that left nine persons dead.

Sources said that Lalon was the second in command in deceased Trinamul leader Bhadu Sheikh’s alleged extortion racket. Bhadu’s murder on March 21 evening allegedly triggered the carnage in Bogtui the same night.

Lalon, who has been absconding since then, has been under the scanner of the central agency ever since it took over the Bogtui case on March 26 following a Calcutta High Court order.

Bhadu’s murder is also being investigated by the CBI.

“The CBI had arrested four persons from Mumbai last week. Their interrogation threw up the name of Lalon’s father-in-law Samir Sheikh repeatedly. Samir Sheikh was first called at the camp office and later arrested as he was not cooperating with the agency,” said a CBI source.

Samir becomes the 26th person to be arrested in the Bogtui carnage case.

Multiple sources said Lalon was with Bhadu when he was killed on March 21 but at a distance from the site where the Trinamul deputy chief of Barshal gram panchayat was attacked with bombs.

“Lalon was also the most vocal among those seeking a retaliation after Bhadu’s murder and he is known to have played an active role behind the carnage and killings,” said a police officer.

CBI sources said the agency was hunting for Lalon since day one.

The sleuths will now try to get details of Lalon’s locations by interrogating Samir, who is suspected to have played an important role in the carnage.

The CBI is also trying to zero in on those who were very close to Bhadu to find out if they had any role before and after his murder.

CBI sleuths also visited the three-storey house of Bhadu at Bogtui More.

Sources said the house had at least six CCTV cameras and the CBI officials wanted to check the footage of those cameras. Sources said sleuths were also trying to figure out if anything had been taken out of Bhadu’s house in the aftermath of the murder.

A CBI team also visited Kasthogarah village of Rampurhat subdivision to interrogate Tabila Biwi, Bhadu’s wife.

CBI officials on Sunday summoned carnage eyewitness Mihilal Sheikh at its camp office in Rampurhat and collected photographs and other documents of his seven family members whose bodies had been charred beyond identification.

“I have handed over photographs and other documents of my family members whose charred bodies were found from the house of Sona Sheikh (on March 22 morning). The officials said our samples would also be collected very soon for a DNA test,” Mihilal said after coming out from the CBI camp office on Sunday afternoon.

Samples of the bodies had already been taken during the post-mortem. for the DNA test. The CBI had promised the DNA test for identification of kin after Mihilal and other family members alleged that the bodies were buried in their absence on the night of the carnage.