Biswajit Debnath, alleged mastermind in the Sachin Mukherjee murder, surrendered at an Alipore court on Monday afternoon.

Debnath, in his mid-30s, turned himself in around 2.30 pm and was remanded in judicial custody till February 24 by additional chief judicial magistrate Manjit Singh.

Debnath and Mukherjee were partners in politics and business, till they fell out some months ago over land deals in Garia, Bramhapur, Sonarpur and Baishnabghata-Patuli.

Police said Debnath?s name surfaced during the interrogation of Biswajit Saha, who was arrested last week in connection with the murder of the Trinamul Congress vice-president.

Saha apparently told police that Debnath had promised him and two of his associates Rs 1 lakh to kill Mukherjee. Of this, the trio had received Rs 30,000 as first instalment in Kharagpur on February 6, the day after the murder.

Debnath, a resident of Garia, was an active Trinamul member who fell out with the party brass but remained close to Mukherjee. He is said to have returned to the party fold, an imputation the Trinamul leadership refuses to accept.

Apart from Debnath, police had issued arrest warrants against Babai, alias Konkal, and Probir Sarkar, alias Praveen.