Police early today released Khairul Islam Sajib, senior joint convener of Narayanganj district Jubo Dal and son of BNP's Narayanganj-3 lawmaker Azharul Islam Mannan, after six hours of interrogation.

Sajib was taken to the Detective Branch (DB) office in Dhaka yesterday and was released into the custody of his relatives around 1:30am today.

Confirming the development, Dhaka Metropolitan Police Additional Commissioner (DB) Shafiqul Islam told The Daily Star that Sajib had been questioned over "several issues" before being released.

"We questioned him regarding a number of matters and later handed him over to his relatives," he said.

About the allegations that led to Sajib's detention, Shafiqul said, "We had some information and spoke to him about those issues."

When asked whether the questioning was linked to any extortion allegations, he said, "We are not ruling anything out."

The DB chief, however, did not disclose any specific allegation against Sajib or say whether any case had been filed against him.