The C4 material, about the size of a bar of soap, is not commercially available. It was of "high military caliber" and may have been taken from a military base, according to officials. This amount would have been enough to level the bus terminal according to law enforcement.
According to police, the material was left in the locker to be picked up at a later time. Was the perp part of a crackdown on terrorism that saw the arrest of the famed "Dancing Israelis"?
This was not the first - in early 2001, police bomb squads in Philly were kept busy by a series of unexploded devices found in the area, according to this article.
Bomb material removed from bus station locker
EXPLOSIVES FOUND IN PHILLY
Cops removed the bomb-making material without incident.
"If it had gone off, it would have blown up the whole terminal," said Philadelphia police spokesman Sgt. Roland Lee. "It was very disturbing because that location is heavily traveled."
Authorities said they found five ounces of C-4 explosive - which looked like and was about the size of a bar of soap - in a black, soft-sided suitcase with about 1,000 feet of detonation cord.
It had been checked in a locker at the station Sept. 29, police said. Bus station workers removed the suitcase from the locker yesterday and opened it because the time limit for the locker was long expired.
Investigators said there was no imminent threat of explosion because a detonation cap was not attached.
"My sense is that whoever put it there . . . meant to just store it for a short period of time and pick it up, and for some reason never showed up or showed up too late," said Philadelphia Police Commissioner John Timoney.
'Strictly military stuff'
The discovery came amid heightened security around the nation's transportation hubs following the Sept. 11 World Trade Center and Pentagon attacks.
Police and agents from the Bureau of Alcohol, Tobacco and Firearms evacuated the terminal while bomb squad cops removed the suitcase and the building was searched. The station reopened four hours later.
Philadelphia police said they are investigating the incident along with the FBI and other federal agencies. Police also were checking fingerprints and surveillance tapes of the terminal for clues as to who checked the suitcase.
"We think we have some good forensic evidence, and there was some videotape, which was confiscated," Timoney said. "It's of poor quality, but we're trying to enhance it right now."
Explosives experts said C-4, developed for the U.S. military during the Vietnam era, usually comes in units roughly twice as large as the material found in the suitcase. Like putty, it's easy to mold and far safer to transport than less powerful dynamite.
"It's strictly military stuff" and "very dangerous," Lee said.
C-4 is not available for consumer purchase like the fuel oil and fertilizer used to make the bomb that destroyed the federal building in Oklahoma City in 1995.
Authorities have said C-4 was used in the bombing of the Navy destroyer Cole in Yemen a year ago that killed 17 sailors. That attack has been linked to Osama Bin Laden's terror network.
Explosives found in Philadelphia bus station
An FBI spokeswoman said there was no evidence linking the explosive to terrorist attacks.
Also found was 1,000 feet of military detonation cord, but no blasting cap, police said.
The amount of explosive was about the size of a bar of soap, weighing about 5 ounces, police said.
"It had the potential, obviously, of creating quite a bit of damage," said Police Commissioner John Timoney.
"Whoever put it there meant not to blow up the station, but to store it there," he told CNN. "For some reason, he never showed up or showed up too late."
The suitcase had been placed in a locker at 2:43 a.m. September 29. When it had not been claimed by October 3, a terminal worker removed it and placed it unopened in storage. After two to three weeks, abandoned luggage is opened and the contents -- typically clothes -- are given to homeless shelters. Friday morning, a worker opened the bag and saw the putty-like explosives and cord and called police. Timoney described the explosives as "high military caliber."
Agents from the FBI and the Bureau of Alcohol Tobacco and Firearms are involved in the investigation, he said. "We think we have some good forensic evidence," he said, including fingerprints and fibers that will be tested for DNA.
The Secret Service has offered its expertise in enhancing a poor quality videotape that may also prove useful to investigators, he said. "Hopefully, we'll come up with something."
No letter or threat was inside the bag, police said.
Police evacuated the building at 10:30 a.m. and took the suitcase to the police academy, where it was x-rayed and examined.
The contents were confirmed late Friday afternoon to be C-4.
"I have no information about any connection to the September 11 attacks or any other terrorist activities," said FBI Special Agent Linda Vizi.
Bus service had been halted for two hours, and police evacuated buildings and closed down streets within a two-block radius of the terminal. Though Timoney said the quantity involved "could have taken the building down," an explosives expert told CNN that the amount in question could have cause significant damage, but would not have leveled the terminal.
Explosive found in Philadelphia bus station probably stolen from military, agents say
Associated Press | October 22, 2001PHILADELPHIA -- The plastic explosive found in an abandoned suitcase inside a city bus terminal last week was probably stolen from the U.S. military, federal agents said today.
The Bureau of Alcohol, Tobacco and Firearms was still working to trace the explosives Monday night. Investigators have concluded that the one-third pound of C-4 and 1,000 feet of blasting cord were not sold commercially or stolen from a manufacturer.
"This batch was made some time ago, and it went to the military," ATF spokesman Darrell O'Connor said. "Hopefully, records are available that will tell us exactly where it went and how it was supposed to have been used."
The explosives, which police said were powerful enough to level the building, were discovered Friday inside an abandoned suitcase at the Greyhound terminal.
The suitcase had been placed in a public locker at the bus station on Sept. 29, then moved by workers to a storage room when it went unclaimed.
Since the discovery of the explosives, Greyhound has strengthened security measures at bus terminals nationwide.
Kristin Parsley, a spokeswoman for the Dallas-based company, said security cameras in terminals have been repositioned to cover all public-storage areas. Greyhound is also checking lockers more frequently and immediately removing unclaimed items, she said.
Public lockers at the Philadelphia terminal have been closed indefinitely. Parsley said Greyhound believes lockers in other locations are safe, and that there are no plans to remove them.
"It was an isolated incident. This is the first time that anything like this has happened," Parsley said.
About 35 cities have the type of electronic storage lockers used in the Philadelphia terminal. Another 260 bus depots have coin-operated lockers. All are self-serve, so depot managers have no control over what is placed in them.
Greyhound added extra security guards at its busier terminals after the Sept. 11 attacks, Parsley said. Each bus is now also being checked three times before and three times after each trip, rather than once by the driver, she said.
In 20 cities the company has begun screening passengers with a handheld metal detector before they board. Parsley said the program is still in a trial phase, but has been successful so far and may be expanded.