Two representatives of the US Federal Bureau of Investigation (FBI) yesterday met a team of the Detective Branch of police in the city to know about the investigation into the gruesome double murder in Kalabagan.

The FBI representatives offered their support to the DB particularly to carry out DNA tests on samples collected from the crime scene and a bag left by the killers, said a source in DB.

The DB investigators told the FBI officials that they have already sent some samples to the DNA laboratory at Criminal Investigation Department.

Home Minister Asaduzzaman Khan said he was not aware of whether the FBI made any written proposal for helping the DB in the investigation.

“If they want to extend support, we'll welcome them,” he told The Daily Star.

US Secretary of State John Kerry in a press statement on April 25 said, “We offer our full support to the government of Bangladesh as they investigate these murders and bring the perpetrators to justice.”

Xulhaz Mannan, a USAID staff and also editor of the country's only known LGBT magazine Roopbaan, and his friend Khandaker Mahbub Rabbi Tonoy were killed inside the former's Kalabagan flat on Monday afternoon.

Xulhaz was a former protocol officer of ex-US ambassador to Bangladesh Dan Mozena.

Two cases were filed with Kalabagan Police Station on Monday night in connection with the killings.

“As Xulhaz was a former staff of the US embassy, the country is concerned about whether he was killed for his affiliation with the embassy,” said a DB investigator on condition of anonymity.

The DB does not think that Xulhaz was killed for his previous link to the US embassy. Rather, he might have been killed for being a gay rights activist, added the investigator.

The detectives are yet to make any arrest in connection with the double murder.

Dhaka Metropolitan Police Commissioner Asaduzzaman Mia had earlier said they seized a mobile phone left by one of the killers. Kalabagan police, however, said there was no mobile phone on the seizure list.