Jurgen Kantner, with his wife, Sabine Merz, who herself was killed during the kidnapping

Jesus Dureza, the adviser dealing with Muslim rebel groups, on behalf of Philippines president, Rodrigo Duterte, condemned the killing of Kantner as barbaric, saying the Philippine military and other groups “exhausted all efforts to save his life” up to the final moment.
“We grieve as we strongly condemn the barbaric beheading of yet another kidnap victim,” Dureza said in a statement. “We all tried our best. But to no avail.”
In Germany, Foreign Ministry spokesman Martin Schaefer said German experts were evaluating the video to determine whether it was authentic, but that if it was, it’s “deeply shocking.”
“It makes you question what can lead people to commit such a barbaric crime, but, at the moment, I’m not in a position to say whether the video’s authentic,” he said.
He would not give any details on possible negotiations with the kidnappers, including whether there was a ransom demand, citing government policy and saying that “public comment never helps in finding a solution” in such cases.
However, local media reports said talks had been conducted with the militants over Mr Kantner’s release in exchange for 30m peso (£500,000), but that they later broke down.
Kantner was abducted in November 2016 after he  and his wife Sabine Merz, were attacked by the militants while cruising Philippine waters in their 53-foot yacht. Merz was killed during the kidnapping, reportedly after trying to fight back against the militants with a shotgun.
Abu Sayyaf announced themselves in November, that its gunmen had kidnapped Kantner and killed a woman sailing with him off the coasts of Sabah state in neighboring Malaysia. Villagers later found a dead woman on a yacht with the German flag off Laparan Island in Sulu province in the southern Philippines. Coincidentally, the same couple were abducted by Somali pirates and held hostage for 58 days off the Gulf of Aden in 2008, and later freed, officials said.
Abu Sayyaf has been active largely through maritime piracy for over three decades, and was responsible for the Philippines’ worst terror attack, the Superferry bombing in 2004, which killed around 100 people. In 2014, after pledging allegiance to ISIS, they escalated to regularly kidnapping and beheading sailors as a means of supporting the Middle East-based group.
The Philippine militants which has been Blacklisted by the U.S. and the Philippines, as a terrorist organization, is holding more than 20 foreign and local hostages in jungle encampments in the country’s south.Abu Sayyaf beheaded two Canadian men in 2016 after separate ransom deadlines lapsed.
Philippine Duterte has ordered the country’s troops to destroy the Abu Sayyaf extremists, saying their ransom kidnappings were embarrassing and were creating a security alarm in the waters bordering the south, Malaysia and Indonesia.
However the kidnappings by the Abu Sayyaf and allied gunmen of passing crews have persisted despite the joint efforts by the three countries to shore up security along their territorial waters