A probe has been initiated in connection with a robbery of Rs 10.5 lakh from a businessman in Karimganj district on Monday night.

An FIR was lodged by the businessman Khasrul Haque, a beter nut trader with Karimganj Sadar police station on Tuesday.

According to the FIR, he started for his native village Banugram around 8pm on Monday night after selling betel nuts at Krishnapur in Hailakandi district.

Khasrul, who had Rs 10.5 lakh with him — which he got after selling betel nuts — was in one of the two trucks which he had hired to ferry betel nuts. The FIR said Khasrul along with the two drivers Aain Uddin and Kabir Ahmed had dinner at a hotel in Badarpur.

Ahmed finished his dinner hastily and left in his truck. Around 9.45pm, Khasrul started with Aain Uddin in his truck. Around 10.30pm, a white Maruti Alto signalled them to stop on Karimganj bypass, around 52km from here. Sensing trouble, Khasrul told Aain Uddin to accelerate, but he stopped the vehicle on the bypass, the FIR said.

After the driver stopped, four unidentified persons came out of the car and dragged Khasrul out of the truck.

They beat up Khasrul, snatched the bag in which he was carrying cash and fled, the FIR said.

Khasrul, who was critically injured, somehow reached Nilambazar and informed Karimganj Sadar police station. He was then sent to Karimganj civil hospital.

He suspected Aain Uddin and Ahmed might be involved in the attack on him.

He told police that only the duo knew about the amount he had with him.

Investigating officer Joynal Uddin Laskar on Wednesday said Aain Uddin had been arrested and Ahmed and one Kabir Uddin were picked up from Nilambazar on Tuesday night. Aain Uddin was produced in a court in Karimganj on Wednesday and remanded in police custody, he said.