A fingerprint and two DNA samples was all authorities needed to arrest Cesar Altieri Sayoc Jr. for his suspected role in mailing out more than a dozen explosive devices to prominent Democrats, FBI Director Christopher Wray said Friday.

Wray told reporters at the Justice Department’s headquarters that one of Sayoc’s fingerprint was found on the package mailed to Rep. Maxine Waters, D-Calif., and that his DNA was found on two other packages. The DNA samples were connected to a sample collected from a prior arrest of Sayoc’s, said Wray.