A total of 16 packages attributed to the would-be bomber were found across the country, all mailed to people and organizations featured in Trump rantings.

The first package was discovered October 22nd at the upstate home of billionaire George Soros, and another was addressed to Hillary Clinton was intercepted by the Secret Service on October 23rd. A package sent to Former CIA Director John Brennan under the address of the CNN building caused a massive police response and the evacuation of the CNN building at Time Warner Center on Columbus Circle while the device was safely removed and sent to the NYPD investigation facility in the Bronx. Other packages in the New York area were addressed to Robert De Niro in Tribeca and another sent to CNN targeting former National Intelligence Director James Clapper.

After examining the devices and packaging, a fingerprint was found that led to Cesar Sayoc, a Florida man who was found living in a van plastered with right-wing rantings and images of Donald Trump. Stickers covering the van's windows featured some of the people targeted in the mail bombs shown with the crosshairs of a gun drawn on their photos. Sayoc had at least eight prior arrests and maintained an active Twitter account spouting out right-wing conspiracies and posting photos of Sayoc's attendance at Trump rallies.

On March 21, 2019, Sayoc pleaded guilty to 65 felonies and was sentenced to 20 years in federal prison.