The Kampong Speu air had settled into a sultry haze.  It was not yet midday - the rains had not yet arrived - and patches of sweat were beginning to seep through Koki Ishiyama’s stiff, cotton shirt.

On October 10, 1973, the former correspondent for the Japanese news service, Kyodo News, turned to his assistant, Vorn Kong, a local stringer he’d formed a close bond with in the year he’d been covering the war in Cambodia.

The pair were about 40km north-west of the capital, close to Oudong mountain, in a beaten-up, rented car. Ishiyama was intent on heading out to a Khmer Rouge stronghold, an area impenetrable by car, so he left his assistant by the road’s edge and set off on a bicycle.

“He wanted to get there; to get the scoop… all foreign journalists were interested in that area, the headquarters of the Khmer Rouge. He had a bag of medical supplies… I do not know if these were for him or for distribution to villagers.

“He looked at me and said, ‘Kong, we all have to be men.’ He said it was his duty as a reporter. He was red in the face and looked very serious. He was very eager to know the real situation, right in the thick of it. I told him not to go but he was persistent. He said ‘It is essential to get this information to the public and I’ll be happy if I get there’.”

Kong never saw Ishiyama again.

The area was laced with peril, but he said his colleague had refused his offer to go along on the trip for fear of him being targeted and captured. Kong helped him arrange his travel discreetly.

“Journalists were, more or less, on their own here. There was no army backing them up,” he said.

It is thought the steadfast reporter was captured by Khmer Rouge militia, held hostage and hauled deeper and deeper into murky jungle and Khmer Rouge camps until he died of disease or illness in 1974. His bones have never been found.

In Phnom Penh the day before they’d left, Ishiyama had pulled out a photograph of his young Tokyo family – his striking wife, Yoko, and his two young children - and in a moment of sincerity, asked his friend to look after them should anything happen.

Last week, two days after the late King Father Norodom Sihanouk’s cremation, a group of former war correspondents and monks in saffron robes gathered for a memorial service for Ishiyama at the nearby Wat Ounalom.

Many were in Phnom Penh for the King’s funeral, but also to commemorate the 37 journalists who perished in Cambodia between 1970-75.

Yoko wept as she knelt by the stupa inscribed with her husband’s name, clutching incense as a monk chanted the Pali scripture.

Although the stupa was completed last year, Yoko wanted to wait until Ishiyama’s friends and colleagues of that time were back to hold the first memorial.

“[For me] to come back now… it’s just to pray for Koki… these people were important to him. He thought the pursuit of the truth was so important. We couldn’t talk over the phone while he was here, but he wrote many letters, love letters and beautiful words to his children. Many of these I read after he disappeared.”

Ishiyama’s daughter was a newborn and his son under two years old when he saw them last, she said.

Yoko remained poised throughout the service but her voice was tinged with melancholy. She has written a book in Japanese chronicling her husband’s life, soon to be published.

In the days after Ishiyama disappeared, Kong attempted to traverse the area where he had left his friend. “I thought I was about to be killed. The road was blocked however, and I could not go any further, I had to go back to Phnom Penh.”

“We tried to search for him for a long, long time,” Ishiyama’s Kyoda colleague, Hideki Ikeuchi, based in Ho Chi Minh City at the time, said at last week’s memorial But in 1981, a woman living on the fringes of Phnom Kchaul (Aoral Mountain - the tallest in Cambodia), came forward with news of Ishiyama’s fate.

“She was a nurse of the Khmer Rouge and she said she had been with him when he died in the field hospital, of disease or malnutrition, or malaria,” Ikeuchi said.

He and Yoko were assisted in their search by an American scholar who was “instrumental in collecting information,” and, in 1996, by current Kyodo correspondent Puy Kea.

A commune council member from Toek Phos district contacted the group in July 2008, telling them he’d found a driver for the Khmer Rouge leaders who could take them to Koh Kley, a village at the foot of Phnom Kchaul where a grave, abandoned and eroded, contained up to 20 bodies, one of which the villagers believed was Ishiyama’s. The team travelled there in January 2009.

“I felt so sad, I was overwhelmed. It provided a sense of closure though… to see that location, to see what he would have seen last… but it made me feel very sad… he must have been so lonely and scared,” Yoko said.

Both Ikeuchi and Kea never met Ishiyama, but both feel he has made a lasting imprint on their lives

“There was limited contact between Cambodia and Tokyo, so his copy would come through me, via mail to Saigon, I’d then type them up. So I felt I knew him that way, through his writing. And he was a wonderful writer,” Ikeuchi said.

“He’d recite Shakespeare to us in Japanese,” American photojournalist Al Rockoff recollected.

“He was a fearless, brave reporter… he was also a careful man, he prepared that trip for half a year… but his idea might have been a bit too idealistic,” Ikeuchi said.

“I felt a connection. I’ve spoken to (former Lon Nol information minister) Chhang Song about that time… he remembered Koki… he said he enjoyed discussions with him, they both loved to sing and would do so together,” Kea said.

“We have never found Koki’s remains… but we feel the case is closed,” Ikeuchi added. “I think he’ll remain in Cambodia, forever.”

In June, 1971, Kong – who had worked for Kyodo since 1970 - was captured and arrested by Viet Cong soldiers with a group of journalists, including Australian correspondent Kate Webb, who was reporting for UPI and AFP, and Cambodian reporter Tea Kim Heang, or “Moonface”.

They were held for 23 days, tied up in a bunker, finally released after convincing the soldiers they were not connected to the government, he said.

“This all shaped the way I felt when I worked with Koki. I had been through it and I warned him,” he said.

“When he arrived he was idealistic, he wanted to be a champion! He was very fast and sometimes I had trouble keeping up.”

Kong’s office was room A14 at the famed Le Royal - New York Times correspondent Sydney Schanberg and a consortium of journalists worked from here, and it was where headcounts were conducted each night.

“Sydney was called the giant – he’d often scream ‘Pran’. Dith Pran and I were friends, often I’d go out with them (on stories). He was on the second floor overlooking the pool so we would often sit and talk… they’d throw (Al) Rockoff into the pool! He was close to Elizabeth Becker, too.”

“Koki was handsome, with glasses, a dashing fellow with short hair, we’d often go for meals at Central market and sometimes high class places.”

On the morning of April 17, 1975, Kong had already filed two stories to his Kyodo bureau chiefs, from his Le Royal office – swathed in UN flags - and was half way through a third when he heard the knock on the door.

“I told them I was just an assistant and hadn’t been writing, although I was the only Kyodo journalist [in Cambodia] then. They said if I didn’t come I’d be responsible in front of Angkar.

“I was taken to Kampong Cham, marched there with other journalists. There were ten of us and I am the only one who survived. I wrestled free and jumped into a ditch and then shrubs, I think they thought I was dead… I walked back to a village and then was captured again, but I said I was a driver. Still, I was imprisoned for six months.”

“I migrated to Tokyo eventually, I was lucky. I remember seeing The Killing Fields and feeling emotional, although parts were embellished. I saw Koki and me in that relationship. He was an honest, sincere journalist and person – he said it was all about the truth, getting the facts right, he had integrity.”