JULINGTON CREEK, Fla. -- Federal, state and local investigators spent hours studying, then detonating what appeared to be two pipe bombs that were delivered Friday to a Julington Creek home Friday.

The improvised explosive device was in a package with pictures of the World Trade Center covering the outside, according to the St. Johns County Sheriff's Office.

The residents of a home on West Pleasant Place, off Racetrack Road, said they were not expecting a package and considered it suspicious, so they called authorities.

The fact that the devices were active, combined with the Twin Towers markings, led authorities to take this case very seriously, immediately requesting that Alcohol, Tobacco, Firearms and Explosives and FBI agents come to the scene.

"We have a Sept. 11 scene -- a scene of New York City prior to Sept. 11," St. Johns County officer Chuck Mulligan said. "After that fact, we're not going to too many specifics about the device itself, certainly we'll let ATF and our investigators look at that."

Adjacent residences were evacuated and the cul de sac closed into the evening as deputies and other officials gathered evidence and interviewed everyone in the area.

"It's kind of scary what it could have done," neighbor Joann Johnson told Channel 4's Adam Landau.

A search of neighborhood found no other suspicious devices.

"Normally, even if someone has designed a package to look as though it's an explosive device, we find nothing explosive inside," Mulligan said. "Certainly different today."

After the devices were "rendered safe," the investigation focused on where the devices came from, how the package came arrived -- whether it was delivered by an individual or sent through the mail or a commercial carrier -- and why it arrived at this particular home.

A special tip line was established for information regarding this incident, with anyone who could assist the investigation asked to call 888-668-4388.