The crude explosive devices delivered to the home of billionaire Democratic donor George Soros and the Time Warner building in New York appear to have been pipe bombs.

CNN reported that those two devices were similar to those addressed to the home of former President Bill Clinton and his wife Hillary Clinton in Chappaqua, New York, and the office of former President Barack Obama in Washington D.C.

The Centennial Olympic Park bombing in Atlanta, Georgia, in 1996 was the result of a pipe bomb. In December 2017, a terrorist inspired by ISIS attempted to detonate a pipe bomb strapped to his body in New York. This year, a Minnesota man who wrote of "armed rebellion" and wanted to spark a "2nd American Revolution" was convicted of possessing pipe bombs.

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Tom Fuentes, a former FBI assistant director, said on CNN that this week's devices appeared to be part of an attempt to influence the midterm elections, describing it as "domestic terrorism - someone trying to cause chaos in our process."

Pipe bombs typically consist of a six inch lead or PVC piping filled to roughly 75 percent of its capacity with gun powder and a fuse. The fillers can include flammable liquids, black powder, smokeless powder, fireworks powder, match heads and other chemicals.

There are so many possible variations in configuring a pipe bomb that it makes it difficult to quantify the effects and damage each can cause. To detonate the explosive, an individual can light a fuse, which triggers the explosion but it is more common for the bomb maker to install a booby trap or remote detonator.

A 2003 report in the Royal Army Medical Corps journal stated: "The use of pipe bombs by terrorist organizations around the world has risen dramatically. The pipe bomb is simple and easy to make and details of bomb construction are freely available from the Internet. Components can be found in most hardware stores and thus give little forensic information."

Unlike other small explosives such as pressure cooker bombs that are filled with shrapnel, pipe bombs are effectively their own shrapnel, catapulting out shards that can cause death and serious injury to those within its immediate radius.

Pipe bombs have been a favorite weapon of both the early military, terrorist organizations, and they have been used in some murders. The Allied Forces used massive pipe bombs at Omaha Beach during World War II.

Billionaire Democratic donor George Soros was sent a "pipe bomb" to his home Monday and two other explosive devices have reportedly been found at the homes and offices of former President Barack Obama and Secretary of State Hillary Clinton.

In addition, the Time Warner building, which houses CNN's New York bureau, was evacuated when a device was found in the mail-room, prompting a 911 call. CNN reporter Anthea Jones said that the device contained "pipes, as well as other material."