Because of his expertise in forensics, Pierre Margot has worked on several international issues. In 1972, he participated, in Northern Ireland, to the investigation of the Bloody Sunday with Doug Lucas and Peter Forest. He then continued his international involvement in 1985, during his participation in the investigation of the Sinking of the Rainbow Warrior. In 1989, while working at the Australian National University in Canberra, Australia, he participated (with Ron Warrener, Hilton Kobus, Milutin Stoilovic and Chris Lennard) to the invention of the Polilight. He participated, among other during his career, to the investigation of the massacres of the Order of the Solar Temple (1994–1997) in Canada and in Suisse as well as on the Omagh bombing in Northern Ireland (1998, with Doug Lucas and Peter Forest).