Bobby Lee Riley, 20, admitted Thursday that he stole mail during a series of thefts at the Homedale post office in June, July and August.
Three times, Riley entered the post office during early morning hours, jimmied some of the locked post office boxes, scooped out the mail and then reached out the open back of the boxes and into adjoining boxes to grab additional pieces of mail.
The thefts were discovered when the thief lost some of the envelopes and other mailed materials and they fell on the floor.
Riley was caught after a surveillance camera was installed and it captured Riley stealing mail on Aug. 24.
Homedale police officers who viewed the tape recognized Riley and he was later taken into custody.
Riley pleaded guilty to one count of theft of mail, during a hearing before U.S. District Judge Edward J. Lodge in Boise.
He faces up to five years in prison when he is sentenced Jan. 6.