Police are yet to find any clue to the bomb blasts that killed a traffic sergeant and injured another ten near the International Trade Fair in Khulna Saturday night.

Senior officials of the Khulna Metropolitan Police (KMP) could not confirm whether attackers wanted to kill anybody or sabotage the fair at the Circuit House Maidan.

However, a police officer told The Daily Star that Sergeant Ariful Islam intercepted seven young men who tried to enter the fair venue without tickets at about 7.00pm Saturday.

The group threatened the sergeant with dire consequences while leaving, the officer added.

A five-member team of the Criminal Investigation Department (CID), dispatched from Dhaka, visited the spot.

Police and other lawenforcement agencies were put on high alert in the wake of the bomb blasts.

Another team under supervision of Deputy Inspector General of Police (Khulna) Enayetullah Dewan has started investigation into the incident.

Witnesses said 29-year-old Arif who was on a motorbike died instantly when a bomb was hurled at him.

Four bombs were thrown from the rooftop of a building owned by Sheikh Zahid, former president of the Khulna Chamber of Commerce and Industry. Police found a pair of shoes on the rooftop, allegedly left by an attacker.

Police recovered splinters of the bombs, two cartridges and three bullets of the sergeant's revolver, which was smashed in the explosion, said Sub-Inspector (SI) ABM Faruque of Khulna Police Station. A case was filed under the Explosives Act.

Deputy Commissioner of the KMP (headquarters division) Milly Biswas, Assistant Police Commissioner Bidhan Tripura and SI Faruque were inside the fair venue when the bombs went off.

The condition of constables Paritosh and Rahman, among the injured, is critical, said a doctor at the Khulna Medical College Hospital yesterday.

Police arrested 17 people: Uthan Gazi, 30, Shahidul Islam Bappi, 28, Delwar Hossain, 40, Selina Begum, 38, Mostafa, 20, Abul Hossain, 24, Badal Shaikh, 20, Mizanur, 27, Kabir Shaikh, 25, Anwar, 25, Rezaul, 23, Khaleda, 30, Moniruzzaman, 25, Saber Mollah, 40, Abul Kalam, 25, Noor Alam, 30, and Hafizur Rahman, 26.

Meanwhile, the body of the sergeant was sent home to Nagorikoya village under Kumarkhali Upazila, Kushtia.

Participants of the fair expressed concern over the incident, but organisers are willing to continue the fair until March 9, said sources.

Another bomb attack left three constables injured on January 10 at the PTI crossing in Khulna.