Mexican border agents, acting on a tip from their U.S. counterparts, found $2.5 million worth of gold jewelry hidden in a truck hauling crates of watches from California, authorities said Tuesday night. The truck’s driver was arrested but escaped, the Associated Press reports.

The truck originally crossed from San Diego, California, into Tijuana without being stopped, the AP reports. But agents ordered it to pull over before it left the border complex after U.S. authorities called to say it could be transporting stolen goods, said Jorge Vargas, a Tijuana border crossing administrator.

After an exhausting 12-hour search, authorities uncovered a secret compartment hidden under boxes of watches and merchandise documentation, Vargas reportedly said. The compartment was stuffed with jewelry, constituting one of the largest contraband seizures in Tijuana’s border crossing’s history, he said.

Vargas reportedly said the truck’s driver was arrested, but that authorities briefly let him go so that he could make a phone call. The driver promptly took off running and disappeared, he said.

Vargas reportedly said authorities were certain the jewelry was stolen from stores and manufactures in California but that it wasn’t clear where the truck was ultimately heading when it tried to cross into Tijuana.

Legally importing $2.5 million worth of U.S. jewelry would have meant paying Mexican officials 12 million pesos ($1.2 million) in taxes, Vargas reportedly said.

JCK