Colombia's attorney general's office wants the three all former employees of AirScan International Inc. of Rockledge, Fla. to testify in a civil disciplinary investigation of the deaths in the eastern town of Santo Domingo on Dec. 13, 1998, said an official, who spoke on condition of anonymity Thursday.
The villagers were killed by a bomb allegedly dropped from a Colombian air force helicopter.
But investigators have been unable to serve the subpoenas because the Americans have since left Colombia. The official said the attorney general's office has requested assistance from the U.S. Embassy. The embassy said it does not comment on ongoing investigations.
AirScan spokesman John Mansur confirmed that the three Americans Dan McClintock, Joe Orta and Charlie Demmy were AirScan employees and based in Colombia around the time of the battle.
But in a telephone interview Mansur said he did not know whether any company employees had been flying that day.
"If it was something where a bomb was pitched into a town and we were watching, I would have heard about it," Mansur said.
AirScan's Mansur said his company worked in Colombia from 1997 to March 1999 on contracts with oil companies, using a twin-engine Cessna Skymaster, which it owned to detect possible guerrilla attacks on pipelines and oil installations.
The company's clients during that period included Los Angeles-based Occidental Petroleum and Colombia's state oil company, Ecopetrol, Mansur said, which produce oil in Arauca state, where Santo Domingo is located.
An Occidental spokesman in Bogota said AirScan was not working for the company at the time of the Santo Domingo battle. An Ecopetrol spokesman had no immediate comment.
But Mansur said he "would very seriosly doubt" that any AirScan employees provided targeting information to the Colombian military.
Video taken by the Skymaster plane may be key evidence in both the military and civilian investigations into whether the Colombian Air Force helicopter crew dropped a bomb on the civilians, or onto a rebel-occupied forest as the chopper crewmembers assert.
The Air Force has long claimed that the civilians were killed by a rebel-detonated bomb.
In a sworn statement made before the military tribunal and leaked to local media, helicopter crew chief Capt. Cesar Romero said video taken by the Skymaster "staffed with American pilots" backs the crewmembers' version of events.
Colombia's Air Force chief, Gen. Hector Velasco, acknowledged Wednesday it was "possible" that a U.S. civilian instructor was aboard an unarmed Colombian Air Force Skymaster during the battle. He told reporters it was primarily staffed by Colombian Air Force members even if "an American may have gone along."
The Colombian Air Force helicopter crewmember, who spoke to the AP on condition of anonymity, said there were two American pilots aboard the Skymaster and one Colombian Air Force member. He said the Americans had flown over Santo Domingo before the battle and then showed their video to Colombian forces in a briefing at an oil field in Arauca.
McClintock, reached by The Associated Press by phone at his home in Florida, said he did not recall any bombing incident. He described himself as an airplane mechanic and a former U.S. serviceman, and referred further questions to AirScan.
Colombia is receiving $1.3 billion in U.S. aid for its Plan Colombia, a massive anti-drug plan that combines aerial spraying and alternative crops with efforts to target drug barons who in many cases are protected by factions in Colombia's long civil war.
U.S. military advisors and civilian contractors are both involved in the plan. Critics say it is a dangerous militarization of the war on drugs that could draw the United States into the civil war. Supporters contend the support in necessary to reduce the flow of cocaine into the United States and stabilize South America's oldest democracy.
America's Plan Colombia legislation predicated the aid to Colombia on certain human rights requirements. Colombia has not yet met those criteria, and the requirements were waived by the Clinton administration.
The Plan Colombia funding was authorized by Congress in 1998. But the United States has been providing aerial support to drug interdiction efforts in Colombia and Peru for more than a decade.
Last month, three Americans contracted by the CIA were aboard a surveillance plane that accompanied Peruvian jet that shot down a plane flown by Baptist missionaries.
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