The 56-year-old Awami League MP has been missing since May 13 and was last seen in Kolkata.

Akhtaruzzaman, Anar’s childhood friend, is suspected of being the mastermind of the murder. Sources said that Bangladesh is also seeking legal advice on how to question Akhtaruzzaman, who is suspected to be in the US.

On Tuesday, the police found 5 kg of flesh and hair in the septic tank and sewage pipes of the New Town apartment where the MP was allegedly killed.

While the Dhaka police claimed that the arrested accused had murdered the MP and disposed of some of his body parts in the toilet, CID officials said that the samples have been sent for a forensic examination.

According to some CID officials, Anar used to trade gold with Akhtaruzzaman, and the latter planned his murder because he was angry over not being paid a large sum of money following certain business transactions.

Four persons from Bangladesh and one from Kolkata have been arrested in the case so far, while four other accused — Akhtaruzzaman, Siam, Faizal, and Mustafizur — are still absconding. Bangladesh police on Tuesday arrested Saiful Alam, the aide of alleged killer Amanullah, from Jessore district. Amanullah was arrested by Dhaka police earlier.

Investigators believe that Akhtaruzzaman fled to America via Dubai, and Siam to Nepal via Bihar, while the others are likely to be in Bangladesh. A team of CID officials is also likely to visit Nepal to trace Siam.

Anar, a three-time MP from Jhenaidah-4 in Bangladesh’s Khulna district, is suspected to have been murdered in a Kolkata apartment. While the police found blood stains in the flat, his body is yet to be recovered. The Dhaka police and the West Bengal CID are parallelly investigating the case.