May 16, 1999
Web posted at: 10:31 a.m. EDT (1431 GMT)

WEST PALM BEACH, Florida (CNN) -- West Palm Beach and federal authorities on Sunday were investigating a pipe bomb found at a Florida hotel where hundreds of students were arriving for their high school prom.

A "real nasty" bomb was discovered Saturday at the entrance to a ballroom at the Sheraton Hotel in West Palm Beach, authorities said.

Police defused the bomb, but its discovery prompted officials to immediately cancel the year-end dance. About 400 students from Palm Beach Lakes High had been expected to attend.

U.S. Bureau of Alcohol, Tobacco and Firearms Agent Dale Armstrong said a "very alert security guard" at the hotel found the bomb as high schoolers were beginning to arrive. The guard became suspicious when he saw a shopping bag near the entrance to the ballroom about 8:30 p.m., Armstrong said.

The pipe bomb was inside the shopping bag.

"It was a real nasty one," Armstrong said. He said the pipe bomb was filled with nails and other debris that could have inflicted serious injury had it gone off.

ATF agents sent the device to a federal laboratory for further analysis. There was no bomb threat called in to alert authorities of the potential danger, Armstrong added.

Authorities had no suspects in custody Sunday morning.

Correspondent Susan Candiotti contributed to this report.