NEW YORK - Abdel Basset Ali al-Megrahi, the only person convicted in the 1988 bombing of an American jetliner over Lockerbie, Scotland, died in Libya, family members said Sunday, nearly three years after Scotland released him on humanitarian grounds, citing evidence that he was near death with metastatic prostate cancer. He was 60.

The death of Mr. Megrahi, who always said he was innocent, foreclosed a fuller accounting of his role, and perhaps that of the Libyan government under Moammar Khadafy, in the midair explosion of Pan Am Flight 103, which killed 270 people, including 189 Americans, about 30 of whom had New England ties.

Mr. Megrahi, a former Libyan intelligence officer who worked undercover at Libya’s national airline, was found guilty in 2001 of orchestrating the bombing and sentenced to life in prison, with a 27-year minimum. But eight years later, after doctors said he probably would die within three months, he was freed under a Scottish law providing for compassionate release of prisoners with terminal illnesses.

Cheering crowds greeted his return to Libya, escorted by Khadafy’s son, Seif al-Islam, in a grim propaganda coup. But his release infuriated many families of the bombing victims, touched off angry protests in Britain and the United States, and was condemned by President Obama and other Western leaders, including Britain’s Conservative opposition after Gordon Brown, then the prime minister, waffled.

Critics charged that Mr. Megrahi’s release had been a part of Libyan oil and gas deals with Britain. A British Cabinet official admitted that he and the prime minister had discussed Mr. Megrahi with Khadafy’s son at a European economic conference, but denied there had been any deal for his release.