Dhaka, May 15 (IANS): The Bangladeshi police on Sunday arrested a key suspect in connection with the murders of an editor and his friend for which a "Bangladesh branch" of Al Qaeda claimed responsibility.

"The suspect, Shariful Islam Shihab, was detained from a western Bangladesh district," Xinhua news agency quoted a police official as saying.

The police could not say whether Shihab was one of the five killers who were captured on camera while fleeing the crime scene. But it confirmed Shihab's involvement.

"We're questioning him to nab all the killers," said the official.

At least five machete-wielding assailants forcibly entered the house of Xulhaz Mannan, who used to edit "Rupban", Bangladesh's first magazine for the LGBT (lesbian, gay, bisexual and transgender) community, on April 25 in Dhaka.

The assailants stabbed Mannan and his friend Tonoy Fahim indiscriminately, leaving them dead.

During interrogation, the suspect admitted killing Mannan, who previously worked as a protocol officer in the US embassy in Dhaka, and his friend for "anti-Islamic activities".

A number of secular writers, bloggers and publishers in Bangladesh have been killed or seriously injured in attacks perpetrated by Islamist extremists since 2013.