CANNES, France (AFP) ― A documentary on relatives wiped out in the Khmer Rouge’s tyrannical grip on Cambodia in the 1970s earned Cambodian-French director Rithy Panh a major prize at the Cannes Film Festival on Saturday.

Entitled “L’Image Manquante” ― “The Missing Picture” in English ― the 95-minute work earned the top award in the festival’s “Un Certain Regard” category, which showcases films by emerging directors.

Panh, 49, has been previously singled out for praise for other documentaries on Cambodia’s slaughter: “S-21: The Khmer Rouge Killing Machine” (2003) and “Duch, Master of the Forges of Hell” (2012).

“L’Image Manquante” ― based on a memoir by Panh called “The Elimination” ― mixes archive footage of the ultra-left fanaticism of the Khmer Rouge with hand-carved, painted figurines to represent his lost relatives.

In a review, The Hollywood Reporter praised it as “a deliberately distanced but often harrowing vision of a living hell.”

“What I give you today is neither the picture nor the search for a unique image, but the picture of a quest,” Panh said in notes to accompany the film.

The documentary coincides with the trial of the Khmer Rouge’s two most senior surviving leaders at a U.N. court in Phnom Penh for crimes against humanity, genocide and other atrocities.

Another defendant, co-founder Ieng Sary, died in March aged 87, stoking fears that the regime’s ageing leaders may not survive to hear verdicts on their alleged part in the atrocities.

Led by “Brother Number One” Pol Pot, who died in 1998, the Khmer Rouge emptied cities and abolished money and schools in a bid to create an agrarian paradise.

Up to two million people were executed or died from starvation, overwork or torture.

The court has so far achieved just one conviction, sentencing former prison chief Kaing Guek Eav, better known as Duch, to life in jail for overseeing the deaths of about 15,000 people.

The jury prize in the “Un Certain Regard” category went to “Omar,” an enthusiastically-received fictional tale of love and betrayal in the Israeli-occupied territories, directed by Hany Abu-Assad.

Abu-Assad shot to prominence in 2006 with “Paradise Now,” about two would-be suicide bombers.