The Interior Ministry has launched an investigation into a Christian NGO working in Cambodia, after a journalists union claimed they fabricated stories about child prostitution that were broadcast by international news networks CNN and ABC News.

Huy Vannak, an Interior Ministry undersecretary of state and the president of the Union of Journalist Federations of Cambodia, wrote a letter to CNN condemning the “serious errors” in their recent story The Cambodian girls sold for sex by their mothers, highlighting that the young women interviewed were ethnically Vietnamese. The headline was later changed.

At a press conference on Friday, anti-human trafficking police said they would investigate Agape International Ministries (AIM), run by American missionaries Don and Bridget Brewster, after Vannak claimed the pair had “twisted” facts for fundraising.

“The beautiful smile and dignity of Cambodian mothers and girls should not be distorted by AIM for their petty fundraising purpose,” he said.

Ministry of Interior officials just last year praised AIM’s work and gave them a letter of commendation for helping fight sexual exploitation. Don Brewster declined to comment.

The recent coverage featured a CNN journalist returning to Phnom Penh’s Svay Pak district – once a child prostitution hotspot – to interview women featured in a 2013 CNN documentary starring actress Mira Sorvino.

Vannak claimed the brothels of Svay Pak, which cropped up in the 1990s, had “not existed” for 15 years. Attempts to close the brothels began in 2003 and they were declared closed in 2005.