NEW YORK -- The FBI and New York City police are investigating an explosion that blew out part of the wind-shear detection system serving La Guardia Airport on Friday afternoon.
The blast caused no air-traffic control problems but raised concerns about who might have set off the device and why. A one-page handwritten note found at the site linked the incident to the federal raid on the Branch Davidian compound near Waco, Texas, in February 1993.
"This is in response to the Waco incident, for all our fallen brothers," the note read. It also carried a scrawled swastika.
The FBI said it was unclear whether the attack was vandalism, the work of copycats after the attack on an Amtrak train in Arizona last week, or an act of terrorism by an organized group.
"We are going to take it seriously until we know that we should not take it seriously," said Joseph Valiquette, a spokesman for the FBI in New York City.
The police were classifying the explosion as a crime of criminal mischief, but Deputy Inspector Robert Martin, head of the city police special investigations division, said, "We're giving it some significance because of the timing with the anniversary of the U.N. and, of course, other terrorist acts. We are thinking that this is serious."
Authorities would not say what type of explosive was used.
The blast occurred at 4 p.m. Friday at the old Flushing Airport, across Flushing Bay from La Guardia, police said. A police spokeswoman, Officer Kathleen Kelly, said someone had cut through the fence surrounding the old airport and attached "an improvised explosive device" next to what is called a low-level wind-shear alert system remote center.
The equipment, mounted on a utility pole, is one of six remote sensors that measure wind speed and direction and send that information to a central computer at La Guardia. Officials at the airport said the explosion never jeopardized air traffic. The wind-shear detection system was fully operational by yesterday morning.
Agents of the FBI and members of the New York City police
terrorism task force were at the site yesterday, inside a fenced area of the old airport, which is northwest of the Van Wyck Expressway in the College Point section of Queens.
The wind-measuring device was attached to the top of a wooden pole, and a 2-foot-high, 18-inch-wide box, destroyed by the explosion, was connected at the base. Yesterday afternoon, the fencing around the area was cut, leaving a rectangular hole and access to the box.
"It's not your usual telephone pole," Deputy Inspector Martin said. "It's possible it looked like something sophisticated to them."