Sheriff's deputies seized 5,000 pounds of marijuana last February, but thousands of pounds of the pot were later stolen. Agents are now offering up to $40,000 for information.
They say they need specifics to track down the dope taken from an evidence truck.
"We have had a lot of leads and a lot of general information come in, and we've been pursuing a lot of different avenues. Some of which has been promising, some of which has not," said FBI agent Chris Swicker.
Some of the marijuana that was not taken from the truck was buried in a local landfill, but someone dug it up. Agents say within the next few weeks, they expect to charge up to 10 people for that part of the crime.