SAN DIEGO, Texas (AP) — Duval County authorities say they've found nearly 500 pounds of marijuana in a pickup truck they were trying to pull over for a traffic stop. 

Sheriff's investigator Ronald Smithwick tells the Corpus Christi Caller-Times (http://bit.ly/1v0Zra7 ) eight men sprinted from the truck Wednesday when it crashed into a fence following a short chase. They remain on the loose.

Smithwick says the men left behind eight makeshift backpacks of compressed marijuana. He says smugglers typically throw the backpacks over their shoulders and walk through the brush to avoid police checkpoints.

Officials say more than a ton of marijuana has been found similarly in the South Texas county this year. Last year, they recovered three tons of pot in backpacks.

More From ESPN 960 San Angelo