By Hader Glang

ZAMBOANGA CITY, the Philippines

Government troops have recovered what is believed to be the missing body of Canadian kidnap victim Robert Hall, who was beheaded 20 days ago by a Daesh-affiliated group in Sulu in the southern Philippines.

Major Filemon Tan Jr., spokesman of the Western Mindanao Command, said Hall's decaying corpse was dug up and recovered by troops in Talipao town and brought to their regional headquarters.

"It was discovered by local residents who informed authorities of the body," Tan added.

Hall was kidnapped with fellow Canadian John Ridsdel, Filipina Marites Flor -- since released -- and Norwegian Kjartan Sekkingstad from the Ocean View Resort in Barangay Camudmud, Samal City in Davao del Norte Sept. 21, 2015.

Ridsdel was beheaded by the Abu Sayyaf April 25 and Hall beheaded June 13 after ransom deadlines lapsed.

Hall's head was recovered by civilians in front of the gate of the Jolo Cathedral.

"Sekkingstad is the only remaining Samal Island kidnap victim," Tan added.

The new administration of President Rodrigo Duterte is negotiating the release of the Norwegian captive.

Aside from the Norwegian, the Abu Sayyaf is also holding Dutchman Elwood Horn, seven Indonesian sailors kidnapped June 22, and around five locals.

Since 1991, the Abu Sayyaf -- armed with mostly improvised explosive devices, mortars and automatic rifles -- has carried out bombings, kidnappings, assassinations and extortions in a self-determined fight for an independent province in the Philippines.

It is notorious for beheading victims after ransoms have failed to be paid for their release.