Federal authorities in Texas arrested a person Wednesday who they believe is responsible for putting "quite a few" suspicious devices, including those that resemble pipe bombs, in mailboxes in the eastern portion of the state, an official said.

Bureau of Alcohol, Tobacco, Firearms and Explosives spokesman Tom Crowley told CNN that authorities have arrested a male. Crowley would not reveal the name or age of the person arrested.

Details are expected to be released at a Thursday news conference.

Crowley said the person was someone they had been "watching for a while."

The devices were put in blue U.S. Postal Service collection boxes in five Texas counties.

Last month, the ATF offered a $25,000 reward for information leading to the arrest and conviction of the person or people responsible for placing suspicious devices throughout East Texas.

– CNN's Tracy Sabo contributed to this report.