They said test of the powder in their own way showed it had properties of heroin. Samples have been sent to Dkaha and the test report will be available within two-three days, police said here.

If proved heroin, this would be the single biggest haul ever in the country. The price of 53.5 kg heroin is over Tk 53 crore, police said.

The truck was seized after a long chase on Saturday. Police sources said the way the truck was fleeing also raised suspicion among them that it was carrying contrabands.

Police arrested the driver and the helper of the truck. Police and witnesses said local people on suspicion detained the loaded truck (no. Dhaka-Metro-Ta-02-0750) near Barisal Cadet College in Babuganj upazila on Barisal-Dhaka highway, 11 kilometers from Barisal city at about 3-30 pm on Saturday.

Being detained, the driver informed one Farid Molla, who was in the city. Soon after Mizanur Rahman, Officer-in-charge of Barisal Kotwali police station rushed to the spot and freed the truck. The truck then sped towards Gournadi, escorted by some youths.

The agitated people then informed Barisal Police Superintendent Mainur Rahman Chowdhury. He ordered highway patrol police to detain the truck 'at any cost'.

Assistant Sub-inspectors Md. Shamim and Ranjit Kumar Dutta chased and signaled it to stop. But it ignored. They then overtook the truck and stopped it at Kasba in Gournadi upazila on the highway at about 4-30 pm on Saturday.

Police took it to Gournadi thana.

Police unloaded the goods and made a seizure lists of the goods in presence of Gournadi Upazila Nirbahi Officer (UNO) S M Mahfuzul Huq, Gouranado thana OC Robiul Islam and other officials.

Unloading and listing of goods continued till early morning Sunday. Police also recovered Tk 1,70,000 from the helper and driver.

They recovered fabrics and garments worth about Tk 77,21,850 and two small drums hidden under those.

The tow drums contained 53.5 kgs of 'white powder'.

The Police Superintendent and the Additional Police Superintendent also visited the spot.

OC Robiul Islam lodged a case and arrested truck driver Chunnu Mia, 45, and helper Monu Mia, 40, two brothers hailing from Takshail village in Nagorkanda of Faridpur district.

They were produced before court, which sent them to jail.

Asked about the huge amount of money (Tk 1,70,000), they told police during primary interrogation at the thana that they were given it 'manage police and extortionists on the way.

They also told police that they came to Barisal in a pickup (no. Dhaka-Metro-Aa-422) Saturday morning along with Farid Molla, also from Faridpur, who owns the truck and the pickup.

The goods were loaded from a trawler at Dapdapia ferry terminal. Farid Molla asked them to drive the truck up to Faridpur and wait for him there.

They started for Faridpur and Farid Molla remained in Barisal city.

Some sources claimed that smugglers and drug dealers in the region are involved in the matter.