The most beautiful and haunting words in John Pirozzi's vibrant documentary Don't Think I've Forgotten: Cambodia's Lost Rock & Roll are heard at the beginning: “When we were young, we loved being modern.” That line has the succinct poetry of a song lyric, and the still photograph that accompanies it — of a radiant young woman in a striped minidress and white go-go boots — is a kind of visual music. The woman in the picture, Sieng Vanthy, was a pop singer in late 1960s/early 1970s Cambodia, the setting for a brief but mighty rock & roll renaissance that few outsiders know about: Under the reign of Prince Sihanouk, who strongly encouraged development of the arts, young Cambodians invented their own brand of pop, a melding of the country's traditional styles with Western influences and Afro-Cuban rhythms. But with the Khmer Rouge invasion, in the spring of 1975, the music disappeared, and not just because it was banned: As part of their campaign to purge all Western influence from the country, Khmer Rouge dictator Pol Pot and his regime systematically put intellectuals and artists to death, including musicians. With Don't Think I've Forgotten, Pirozzi resurrects and revives this ghost music, breathing life into it once again.

Because the Khmer Rouge destroyed so many films, books and works of art — not to mention mere personal effects such as family photographs — very little archival footage of the era has survived. But almost miraculously, many recordings have been preserved, in some cases because music had been transferred to cassette before the Khmer Rouge could destroy citizens' 45s and LPs.

It has taken Pirozzi some 10 years to complete Don't Think I've Forgotten, and the result isn't just a rich patchwork tapestry of powerful and ebullient music but a mini cultural history of a country that Americans know little about — other than that we bombed it during the Vietnam War, which ultimately helped Pol Pot and his followers gain a foothold.

Pirozzi introduces us to two stars who ushered in the country's golden age of pop in the '50s and '60s, figures considered legendary in Cambodia: Sinn Sisamouth, a crooner whose silky phrasing could give Sinatra a run for his money, and Ros Serey Sothea, a bouffant-haired sophisticate whose rippling intonation has a tart-edged sweetness. The music that these two recorded, separately and sometimes together — they were friends and colleagues, and Sisamouth considered himself Sothea's protector — is lush and arresting, and the English translations of the Khmer lyrics are stunning by themselves: These are songs in which a lover might be compared to a luminous moon or a plush, quiet forest. They're rooted in love and respect for the natural world, even if the Cadillac tailfin–cool arrangements would be right at home in a cocktail lounge.

We see rare footage of Cambodia's first guitar band, Baksey Cham Krong, a three-piece outfit that pre-dated The Beatles, its members dressed in trim matching suits: Their chief inspiration was Cliff Richard and the Shadows, and you can hear it in their galloping, percussive melodic lines — this is early rock & roll that carries the echo of the sea.

In the 1970s, American troops entered Cambodia, bringing Hendrix and Janis Joplin records with them, and the local musicians picked up new influences. Bands like Drakkar, a groovy bunch of guys in tunics and bellbottoms, pushed for a psychedelic sound laced with fuzz and reverb, a brash, youthful shout of joy that feels like, had the world not gone suddenly mad, it might have heralded for the country a new era of discovery and freedom.

Pirozzi has made one previous documentary, Sleepwalking Through the Mekong, about the band Dengue Fever, whose lead singer is from Cambodia. Here, he's taken great pains to track down both the surviving musicians and the family members of those who didn't survive. The first two-thirds of Don't Think I've Forgotten is a pure and joyous celebration of the music. The last third is an avowal of just how potent rock & roll can be.

Sothea was a farm girl from the country — her mother allowed her to go to Phnom Penh to pursue a singing career as a way of helping to support the family. It's unclear exactly what happened to Sothea after the fall of Phnom Penh, when the Khmer Rouge forced the city's inhabitants into the country in an aggressive move to turn a progressive, optimistic society into a regressive, agrarian one. They killed more than 1.7 million people in their four-year reign, and Sothea clearly represented everything they sought to destroy. Sothea's sister, her bones grown delicate with age, survives her; her simple assertion of how much she misses Sothea — still — is wrenching.

The girl in the minidress, Sieng Vanthy, also survived, though she died before the film was completed. A dignified, well-groomed woman with perfectly coiffed dark hair, Vanthy describes what it was like to be young in Phnom Penh in the early '70s. Then, with tears in her eyes, she explains how she survived: by telling the authorities she was a banana seller.

The Khmer Rouge were unseated in 1979, and only then were the survivors able to begin rebuilding their country, and their culture. Don't Think I've Forgotten is a testament to how much a song can mean: You can destroy the vinyl it's been recorded on, but the sound itself, and all it stands for, is indestructible. Groove is in the heart.

DON’T THINK I’VE FORGOTTEN: CAMBODIA'S LOST ROCK & ROLL | Directed by John Pirozzi | Argot Pictures | NoHo 7

Advertising disclosure: We may receive compensation for some of the links in our stories. Thank you for supporting LA Weekly and our advertisers.