OXFORD, Miss. — Investigators haven’t found any ricin in the house of Mississippi man accused of mailing poisoned letters to President Barack Obama, a U.S. senator and a local judge, according to testimony Monday from an FBI agent.

Agent Brandon Grant said that a search of Paul Kevin Curtis’ vehicle and house in Corinth, Miss., on Friday did not turn up ricin or ingredients for the poison. A search of Curtis’ computers has found no evidence so far that he researched making ricin.

“There was no apparent ricin, castor beans or any material there that could be used for the manufacturing, like a blender or something,” Grant testified. He speculated that Curtis could have thrown away the processor. Grant said computer technicians are now doing a “deep dive” on the suspect’s computers after initially finding no “dirty words” indicating Curtis had searched for information on ricin.

Through his lawyer, Curtis has denied involvement in letters sent to Obama, Mississippi Republican Sen. Roger Wicker, and a Lee County, Miss., judge. The letters, bearing a Memphis, Tenn., postmark, were detected beginning April 15.

Curtis’ lawyer said in court that someone may have framed Curtis, suggesting that a former co-worker with whom Curtis had an extended exchange of angry emails may have set him up.

Still, Grant testified that authorities believe that they have the right suspect.

The judge adjourned the hearing until this morning.