A former Navy sailor in Utah has been take into custody by the FBI in connection to several suspicious packages to the Pentagon, the White House, and Sen. Ted Cruz's office, which were feared to have contained ricin.

The suspect, identified by the U.S. Attorney's Office in Utah as William Clyde Allen, 39, was taken into custody Wednesday in Logan, Utah, according to the Herald Journal.

Investigators told Fox News that one of the envelopes addressed to either Defense Secretary Jim Mattis or the Navy's top officer, Adm. John Richardson, had a return address that raised suspicions that a former sailor had sent it.

Two suspicious envelopes were mailed to the Pentagon this week that contained a substance suspected to be ricin.

Pentagon spokesperson Dana White told reporters in a statement Wednesday that a preliminary analysis shows "the substance was castor seeds, from which ricin is derived." He added, "The FBI is still investigating."

The packages, which never made it into the Pentagon, were screened at a mail processing facility separate from the building.

The Secret Service said Tuesday it had received a “suspicious envelope” addressed to Trump that never made it to the White House. The Secret Service said it was working with law enforcement partners to investigate.

Two people were taken to the hospital Tuesday after being exposed to a “white powdery substance” at Cruz’s office in Houston. The Houston Fire Department later said tests came back negative for any hazardous substance.