FBI arrests suspect near Seattle in DC area suspicious packages case The FBI is analyzing the packages.

A Washington state man has been charged with mailing more than a dozen packages with what appeared to be homemade explosive devices inside to military bases and CIA headquarters in the Washington, D.C. area, according to federal prosecutors in Seattle.

Earlier Tuesday, after five suspicious packages were found, the FBI said it was possible others were mailed to additional mail processing facilities in or near the nation's capital.

Thanh Cong Phan, 43, was arrested at his residence without incident in Everett, Wash., Monday by the FBI and the Snohomish County Sheriff's Office, officials said, and prosecutors revealed new details during Phan's initial court appearance Tuesday afternoon.

Phan became a suspect in the case when U.S. Postal Service inspectors traced the tracking information on one of the packages to the Mill Creek, Wash., post office's self-service kiosk and surveillance photos from the time of the mailing appeared to show Phan.

Among the facilities packages were mailed to include the U.S. Secret Service White House mail screening facility and FBI headquarters in Washington and CIA headquarters in Langley, Va., officials said. Other facilities that received packages included the National Geospatial Agency and four military installations in the Washington area, including Fort Belvoir and Fort McNair in suburban Virginia.

At least one of the suspicious packages sent to the military and government facilities included a long, rambling and largely unintelligible message, printed out on white paper, a source familiar with the case tells ABC News.

The message makes multiple references to “synaptic frequency” and President Donald Trump, the source said.

At one point the note reads: “President Trump business man we want $250 million all you dead,” according to the source.

In court, prosecutors said each package contained a typewritten letter with ramblings about neuropsychology, mind control, and other subjects including terrorism.

Each package also contained what appeared to be a homemade explosive device – a glass vial/bottle containing an unknown black substance with a fuse and small black GPS device, prosecutors said.

Phan was previously known to the Secret Service, after sending letters to the White House, sources told ABC News, and prosecutors said Phan has sent hundreds of letters or emails to various government agencies containing similar incoherent ramblings.

Each package was collected for further analysis at the FBI lab at Quantico, Va., and at least one contained explosive material, the agency said.

Officials at Fort Belvoir in suburban Virginia confirmed to ABC News Monday night that a suspicious package was found there that afternoon, and was contained and rendered safe.