Police believe these militants had transferred the victim to the Al-Qaeda-linked Abu Sayyaf group that is currently holding at least five other hostages. The son of 61-year-old Doroteo Gonzales identified his father's face on Monday after police took on the case. His family had been warned that Gonzales would be killed if they did not pay the ransom of 25 million pesos ($525,000) by Saturday. Gunmen captured Gonzales from his home in Zamboanga city on April 25 and delivered him into the hands of Abu Sayyaf rebels on nearby Basilan Island. The extremist group, infamous for its brutality against Christians and foreigners, has ramped up its efforts to raise money for its activities by embarking on a kidnapping spree throughout the southern part of the country. Christians are often favored targets for these kidnappings. Just last month, militants beheaded another Christian farmer, Cosme Aballes, whom they had taken captive after raiding a Christian community in the same province. According to the BBC, the Philippine government says the radical Muslim group has been trying to evict Christians from its Basilan Island base. Abu Sayyaf and other Muslim militants have been warring in the southern Philippines for almost 30 years to establish an independent Islamic state. In 2007, Abu Sayyaf rebels ordered civilians to deliver the severed heads of seven kidnapped Christians to military outposts in Jolo, another southern Philippine island. Three teachers, a lending-firm collector, and a peace activist are known hostages on Basilan Island. In Jolo, the extremist group is still holding Italian Red Cross Worker Eugenio Vagni, who was captured along with his two colleagues in January. ICC's Regional Manager for East Asia, Natalia Rain, said, "Imagine living in a state where you know you may be seized from your home at any moment and have your fate thrust into the hands of radical terrorists. The brazenness of men who would behead an elderly man for his impoverished family's failure to pay an outrageous ransom should wake us up to the horrifying reality of this thirty-year conflict."