"We have arrested 13 persons so far. We are conducting raids to arrest the other culprits," Cooch Behar police superintendent Santosh Nimbalkar told over phone.
Nimbalkar himself was leading the raids.
The incident occurred early on Thursday in Ketarhat of Putimary-Phuleshwari Gram Panchayat area under Cooch Behar 1 administrative block.
The two victims- Prakash Das (35) and Rabiul Islam (40) - were caught by the locals while they were passing the area in a pick-up van.
Eyewitnesses claimed the mob got enraged when they saw the vehicle did not have a number plate and found a cow being carried in it. The locals started grilling the duo and after a while the beatings started. The cow was released in a nearby field.
"The mob then torched the van. Both the victims had earlier been arrested on the charge of cattle smuggling. While Prakash was a resident of Mathabhanga, Rabiul hailed from Dinhata in the district," said Nimbalkar.
Personnel from the Kotwali police station reached the spot after some time, rescued the youths and admitted them to Cooch Behar Medical College Hospital where they later died.
Eyewitnesses said rumours of cattle smugglers moving in the area were floating for the past few days.
Cooch Behar district has a 549 km border with Bangladesh, of which more than 300 km is fenced, and the rest is open. A substantial part of the open border is riverine.
Eight battalions of Border Security Force personnel are deployed on the border.
"Although border crimes such as smuggling, infiltration and property offences have considerably decreased over the years, cattle smuggling still continues in some portions of the border, specially the riverine border," said district administration officials.
The work of border fencing and construction of border roads is in progress.
( With inputs from IANS )