A master bomb maker who once targeted commercial airliners and was suspected of aiding the Iraq insurgency has fled to Lebanon, an FBI official has confirmed.

There is information that 73-year-old Abu Ibrahim was reportedly in Tripoli, the official said earlier this week. The official spoke on the condition of anonymity because the investigation is ongoing.

The Palestinian terrorist is accused of multiple bombings in the 1980s. He was indicted in the 1982 bombing of Pam Am Flight 830. The explosion killed a 16-year-old boy and wounded more than a dozen passengers as the plane headed to Honolulu from Tokyo.

The FBI has been looking to catch Ibrahim for decades and has recently increased its efforts to arrest him. In April, an FBI committee recommended Ibrahim be placed on agency's list of most wanted terrorists.

The FBI is also trying to tap a State Department reward program to boost the bounty for his capture to millions of dollars. Ibrahim's real name is Husayn al-Umari.

Ibrahim has remained out of reach for decades while living in Baghdad. With the help of the Iraqi Intelligence Service, Ibrahim ran a much-feared terrorist organization called "15 May," which was named for the date Israel was founded.

Ibrahim, a devout Sunni who was born in Tripoli, Lebanon, is suspected of carrying out more than two dozen attacks on mainly American, Israeli and Jewish targets in a career that spans decades.

The Iraqi government also used him to conduct terrorism operations against Syria and Iran. In his book, former CIA spy master Duane R. Clarridge wrote that Ibrahim had a "talent for constructing ingenious machines of death, such as refrigerator trucks whose cooling pipes were filled with liquid explosives."

He trained a slew of operatives in the art of bomb making whose expertise metastasized across the Middle East like Mohammed Rashed and Abu Zyad. Rashed is behind bars at the Supermax maximum-security prison in Florence, Colo. He's scheduled to be released in less than four years.

Some still remain unaccounted for like Zyad.

Zyad, 60, who was born in Bethlehem, assisted Ibrahim in Baghdad in the early 1980s, according to CIA investigative notes obtained by The Associated Press. The notes say Zyad lived in Sudan for two years before leaving for Algiers in 1989. His current whereabouts are unknown.

A former senior CIA official who was stationed in Baghdad after the Iraqi invasion in 2003 said there were serious suspicions that Ibrahim had helped the insurgency.

The official said Ibrahim had recently slipped into Lebanon through Syria after coalition forces began to increase efforts to drive insurgents out of the Mosul area and the Saladin Province in Iraq, where Ibrahim had been operating.

The former CIA official, who spoke on the condition of anonymity because he still works in the Middle East, said that Ibrahim had also gone to Tripoli. Ibrahim's second wife, Selma, is from Tripoli.

"He's got a lot of resources there," the former CIA official said.

Ibrahim's family also has connections to the Badawi Palestinian refugee camp on the northern fringes of Tripoli, according to the CIA notes.

The U.S. does not have an extradition treaty with Lebanon.