SUNNYVALE, Calif. — Police say a UPS worker suspected of threatening a mass shooting at the company's facility in Silicon Valley has been arrested after investigators found numerous firearms and ammunition at his home.

They began searching for 32-year-old Thomas Andrews Sunday night after someone reported he sent threatening text messages to his employer at the UPS facility in Sunnyvale. When officers spotted his car and tried to pull him over, Andrews led them on a brief pursuit before surrendering in San Jose.

Detectives who searched Andrews' apartment uncovered 20,000 rounds of ammunition, five tactical-style rifles, a shotgun, three handguns and body armor.