This screenshot from CNN’s Twitter account shows what CNN says is the explosive device that was delivered to their New York headquarters on Wednesday, Oct. 24, 2018. The package sent to CNN contained a live explosive with wires, a black pipe and an envelope with white powder. Officials said the substance was being tested to see if it was dangerous. (CNN Twitter Account via AP)
An officer with the Uniform Division of the United States Secret Service uses his dog to search a checkpoint near the home of President Barack Obama, Wednesday, Oct. 24, 2018, in Washington. The U.S. Secret Service says agents have intercepted packages containing “possible explosive devices” addressed to former President Barack Obama and Hillary Clinton. (AP Photo/Alex Brandon)
WASHINGTON — Investigators examining the explosive devices sent to high-profile targets in Washington and New York this week will be working to glean forensic clues to help identify who sent them, gathering fingerprints and DNA evidence while tracking the origin of the packages and the components used to make the bombs.