Police have arrested four more persons in the NCP leader Baba Siddique's murder case, including a Haryana native suspected to be an important link between a shooter and the mastermind of the conspiracy.

While Amit Hisamsing Kumar, 29, was nabbed from Haryana, three persons were arrested from Pune late Wednesday evening, which took the total number of arrested accused in the case to 14.

Rupesh Rajendra Mohol (22), Karan Rahul Salve (19) and Shivam Arvind Kohad (20) are all Pune residents, said a police official.

Amit Kumar was suspected to be involved in hatching the murder conspiracy and its execution. Some suspected financial dealings involving him and other accused are also under the scanner, the official said.

Kumar is an important link between one of the shooters in custody, Gurmail Singh, and alleged mastermind Mohammed Zeeshan Akhtar who is absconding, according to police.

As per the preliminary investigation, Akhtar was the common link between shooters and murder conspirators, the official said.

Kumar was nabbed on Tuesday evening from Haryana by a crime branch team and brought to Mumbai on Wednesday morning. He was remanded in police custody till November 4.

Siddique, 66, was shot dead outside his MLA son Zeeshan Siddique's office in Bandra area of Mumbai on October 12.

Investigators have not yet established the motive behind the murder. They are probing the crime from different angles, including contract killing, business rivalry or threats over a slum rehabilitation project in Mumbai.

Those arrested so far include two suspected shooters- Dharmaraj Kashyap and Gurmail Singh- while the main shooter Shivkumar Gautam and two conspirators are on the run.

The investigation so far suggests a five-member Thane-based contract killing module was initially given the contract to kill the former Maharashtra minister.

The module, however, backed out of the contract over disagreement on demanding a sum of Rs 50 lakh for executing the crime and given the clout of the late politician even though they provided logistical support and other help for carrying out the hit, according to police.