FBI Seizes 3 in IRA Plot to Shoot Down British Copters

The FBI announced the arrest Thursday of three alleged operatives for the Irish Republican Army who are suspected of conspiring to develop sophisticated devices for shooting down British helicopters patrolling Northern Ireland.

In addition to two Americans and an Irish national picked up by agents in Massachusetts, Pennsylvania and California, the FBI also obtained an arrest warrant for Peter Eamon Maguire, an Irish national described by British authorities as high up in the terrorist organization’s technical ranks.

FBI Director William S. Sessions said that the three arrested suspects were developing electronic circuitry to be used in remote-controlled explosive devices and were designing rocket delivery systems for use against British targets.

The arrests “demonstrate the high level of technical sophistication being employed by terrorist organizations to further violence worldwide,” Sessions said. He described the investigation as “ongoing” and said that it will continue to try to identify other operatives for the organization, which seeks to drive the British from Northern Ireland.

Those arrested were Richard Clark Johnson, 41, now of Nashua, N.H., but until 1986 an employee of several Southern California aerospace firms; Martin Peter Quigley, 27, an Irish citizen who has been living in Bethlehem, Pa., since April; and Christina Leigh Reid, 25, of Sunnyvale, Calif.

The FBI said that the three face federal charges of conspiracy to injure and destroy the property of a foreign government and possible violation of the Neutrality Act and the Arms Export Control Act.

An FBI affidavit filed in federal court in Boston described extensive steps that the alleged conspirators took to prevent detection, ranging from communicating with one another from outdoor public pay phones on freezing nights to avoiding overseas mail and international phone circuits.

The affidavit, filed by FBI agent Brendan O. Cleary, a counterterrorism investigator, also disclosed the extent to which the FBI went to break the group’s security. Agents used highly secret foreign intelligence wiretaps, including some placed on public telephones, electronic bugs, listening devices implanted in cars and mail covers in the investigation.

In a Dec. 11, 1988, telephone call allegedly arranged by Reid and recorded by the FBI, Johnson was called by Quigley, who sought Johnson’s help in developing countermeasures against low-flying helicopters and aircraft, according to the affidavit.

Johnson, who holds a top-secret clearance for his work in radar technology and imaging transmission for Mitre Corp. in Bedford, Mass., began his career with Hughes Aircraft in Fullerton. He then moved to TRW in Redondo Beach and later to the Jet Propulsion Laboratory in Pasadena and Northrop Corp., in Pico Rivera.

The investigation and arrests trace back to the FBI’s 1982 seizure of tone frequency switches in Newark, N.J., that the Irish Republican Army has sought several times to obtain. These devices, mated to a transmitter, can be used in detonating explosives without interference from an outside signal.

Since the Newark seizure, British and Irish authorities have recovered at least six similar tone frequency switches in unexploded remote control bombing devices linked to the IRA group, according to the FBI.

Attempts by the FBI to trace sales of the switches led to Johnson in 1984, then to a Northrop engineer who said he was operating a part-time industrial security business from his Irvine home. He told FBI agents then that he had bought the switches for experiments that he was conducting with telephone-controlled burglar alarms, the affidavit said.

He acknowledged that he might have sent electronic components, but not the suspect switches, to unnamed relatives in Ireland. He then declined through his attorney to answer further questions.

The affidavit included a monitored Quigley-Johnson conversation last May 27 in which the two men allegedly discussed methods of shooting down helicopters with high-bore machine guns and high-velocity missiles.

“Quigley described his own idea of floating balloons with Kevlar ropes attached to grenades with the aim of entangling the rope in the helicopter’s rotor blades, thus drawing the grenade into the body of the helicopter,” the affidavit recounted.

Reid, who works for an electronics firm in Cupertino and lives in Sunnyvale, was released on a $10,000 personal recognizance bond by a U.S. magistrate in San Francisco, according to Assistant U.S. Atty. Charles B. Burch. An FBI source described the arrest of the three suspects as “premature,” adding that it was not supposed to take place for another six months. The source said that an unspecified problem developed in Boston that forced the bureau to act.

Times staff writer Dan Morain in San Francisco contributed to this story.