U.S. Border Patrol agents of the Tucson Sector found $2.2 million worth of marijuana in the upper compartments of a cattle hauler trailer at a checkpoint near Whetstone. 

Courtesy U.S. Customs and Border Protection

A semi-truck driver was arrested Wednesday and about 4,450 pounds of marijuana seized at a checkpoint near Whetstone.

U.S. Border Patrol agents of the Tucson Sector were conducting a checkpoint on State Route 90 near Whetstone, which is north of Sierra Vista.

As the tractor-trailer loaded with livestock approached the primary inspection area about 8 p.m., agents "noticed the ventilation holes in the upper compartments of the cattle hauler were plugged," according to a Customs and Border Protection news release.

Agents found 188 bundles of marijuana with an estimated value of $2.2 million, states the release. Authorities also found a pistol.

The driver, whose name was not released, was arrested and the marijuana, firearm and tractor-trailer were turned over to Drug Enforcement Administration authorities.

Since the beginning of fiscal year 2014, agents in the Tucson Sector have seized more than 772,000 pounds of marijuana, according to the release.