Gille Coemgáin mac Máil Brigti (died 1032) was the King or Mormaer of Moray, a semi-autonomous kingdom centred on Inverness that stretched across the north of Scotland.
From circumstances, two candidates have been proposed to have led the atrocity: Malcolm II of Scotland or Mac Bethad, who then became the only ruler of Moray.
Gille Coemgáin is believed to have killed his cousin Dúngal mac Cináeda, the younger brother of Malcolm II, in 999.
Both scenarios are entirely credible, knowing archaic medieval customs – nothing exculpatory can be concluded from the marriage, whereas the adoption of the stepson may be a weightier indication.
Gille Coemgáin and Gruoch were the parents of Lulach, a future King of Scotland, fostered by Mac Bethad, whom he succeeded.