Some 5,000 people showed up Saturday in the city of Fukuoka to pay their respects at a farewell ceremony for famed Japanese humanitarian aid doctor Tetsu Nakamura, who was murdered in Afghanistan in December.

“Our family wishes green to spread throughout Afghanistan, as my father hoped,” Ken Nakamura, his 36-year-old son, said at the ceremony at Seinan Gakuin University’s chapel in Fukuoka where mourners honored his longtime contribution to development of the central Asian country.

The 73-year-old doctor, head of the Afghan unit of the Peshawar-kai aid group based in the city of the same name, and five Afghans were killed by armed men who attacked their vehicle in Jalalabad in eastern Nangarhar province on Dec. 4.

Nakamura had been providing medical assistance near Afghanistan’s border with Pakistan for many years. He was also involved in tree-planting activities and a project to improve the water supply in poverty-stricken areas after a drought hit Afghanistan in 2000.

The attendees of the ceremony included Afghan Ambassador to Japan Bashir Mohabbat, who called Nakamura a “permanent hero.”

Photographs of Nakamura and the five Afghans were displayed on the altar during the ceremony.