Abu Sayyaf militants in the Philippines have released a video that shows the beheading of John Ridsdel, the Canadian they had held hostage for seven months, according to the SITE Intelligence group.

SITE is a Washington-based group that researches and monitors networks linked to terrorism.

CBC News is not airing the footage.

Ridsdel, a former Alberta resident, was one of four hostages, including fellow Canadian Robert Hall, held by the Abu Sayyaf militants since last September.

Ridsdel, 68, was described as semi-retired and was the former chief operating officer of mining company TVI Resource Development Philippines Inc., a subsidiary of Canada's TVI Pacific, where he was a consultant.

The kidnappers killed Ridsdel, 68, on April 25 after a ransom deadline they issued had lapsed.

The al-Qaeda-linked group has been known to take hostages for years, and currently has more than a dozen foreign hostages, including another Canadian, in their custody.

The RCMP is investigating Ridsdel's death.