Mystery: Police Find C-4 Explosives in Manhattan Cemetery

NEW YORK — A caretaker doing gardening work at a historic cemetery dug up a plastic garbage bag containing military-grade explosives last year and left it at the site, where it remained until a volunteer told authorities about it Monday, setting off a big police response.

The employee found the C-4 in May or June 2009 after digging down about a foot into the ground at New York City Marble Cemetery on Manhattan's Lower East Side, Police Commissioner Raymond Kelly said. It contained eight bricks of the explosive, which Kelly said couldn't have gone off because there were nothing to detonate it. The spot was near a tombstone but not in a grave.

It was unclear how long the bag had been at the cemetery, but "we believe it's been there for a significant period of time," Kelly said. He said it appeared to be military-grade explosive similar to the material used in the 2005 London transit bombings but that there were no suspicions of terrorism in connection to the discovery.

The caretaker left the bag on the property, by a fence in the back. "It's not clear at this time whether he understood precisely what was in the bag," Kelly said.

More than a year later, a volunteer cleaning the cemetery, a landmark built in 1831, came across it over the weekend and initially left it there before calling police on Monday because it wasn't clear what the material was. Authorities closed nearby streets as they investigated.

The bricks weighed just over a pound, Kelly said. C-4 is a plastic explosive that is more powerful than TNT. It's commonly used by the military because it is easy to shape and relatively hard to set off by accident. C-4's main ingredient is RDX, which also is used in fireworks.

It is relatively insensitive to impact, friction or fire, although large quantities can explode if burned. Even shooting it with a rifle won't trigger the reaction. Only a detonator or blasting cap will do the job properly. Less than a pound of C-4 could potentially kill several people, and several blocks of C-4, weighing about 1.25 pounds each, could potentially demolish a truck.

Kelly said the material from the cemetery was being taken to the police range where explosives are tested. Authorities also were digging around in the cemetery to see if any more material was found.

"We'll have a better idea when the bomb squad looks at it, but it has yellow writing on a green material," he said, adding that's how C-4 is wrapped today. "It's difficult to say with any precision how old this is."

A call to the cemetery seeking comment was not immediately returned. The New York City Marble Cemetery was designated a landmark in the late 1960s. Six members of a branch of the Roosevelt family are buried there, as well as Stephen Allen, former mayor and New York governor.

Police were also looking into two messages that were found in the area to see if there was any connection. One, written in chalk on the sidewalk near the cemetery, said, "I really hope one of you finds this." The other, a note placed on a police car at the precinct near the site, made a reference to Jesus Christ being kept out of the neighborhood and was signed by someone identified as "Jesus Christ."

Kelly said there's no indication to think the three discoveries are linked, but investigators were checking into it.

Neighborhood residents took the scare in stride, watching from police tape and snapping photos, while chatting on cell phones and drinking coffee.

"I wasn't worried, because everyone was out on the street and you have to think if it was something serious it would've been blocked off more," said Danielle Baskin, 22 who lives across the street.