I saw this piece earlier on The National Terror Alert Response Center but didn’t see more developing so here’s the bare bones from Sign on San Diego:

A pipe bomb exploded at a Federal Express building in Webster early this morning. The bomb blew up just before 2 a.m. at the building on 47th Avenue near Federal Boulevard and broke the glass front door and set off the alarm, San Diego police said.

The fire department found a second bomb in the parking lot and detonated it, police said.
An employee at the business was unhurt. He told investigators he thought some boxes had fallen over.

Domestic terrorism or disgruntled employee? Who knows, but Fed Ex is the kind of large corporation that would draw fire from anti-Capitalists so I wouldn’t be surprised to find this was some sort of “direct action” by anarchists.