A cow vigilante team held a tanker ferrying tallow oil captive for four hours at Bhaidesa village of Mansa district on Tuesday night.
Tallow oil, used mostly in making soap, is extracted from beef fat. But the variety derived from Buffalo meat is legal to be processed, despite objections by cow protection groups.
Police said the excise department was verifying bills and documents carried by the driver.
Around 10 members of the Gau Raksha Dal had halted the tanker at 2.30 am, but it took hours as police stations were confused in whose jurisdiction the area fell.
SHO of Maur police station told HT that the tanker was delivering the oil to soap manufacturing factories in Bathinda.
Police, however, refrained from commenting on why no action was taken against the cow activists for illegally detaining the truck and its driver.
Satish Kumar Rajpuriya, national president of the Gau Raksha Dal, defended his activists, saying the oil was being ferried using fake receipts.
“I will ensure that an FIR is registered against the driver,” he said. Tallow oil traders have in the past accused self-styled vigilantes of harassing them in the name of checking cow slaughter.