The House Natural Resources Committee has launched a bipartisan investigation into whether federal conservation grants support organizations linked to alleged human rights abuses overseas.

The probe follows a BuzzFeed News investigation in March that found the World Wide Fund for Nature, or WWF, one of the world´s largest conservation organizations, funded anti-poaching forces that have been accused of torturing, sexually assaulting and murdering indigenous people in Asia and Africa.

In a letter sent to Interior Secretary David Bernhardt on Thursday, Rep. Raúl Grijalva (D-Ariz.), the committee’s chairman, and Rep. Rob Bishop (R-Utah), its highest-ranking Republican, requested a briefing on all international conservation grants the agency has awarded.

The committee is “examining allegations that partner organizations supported by the U.S. Government have played a role in funding and equipping forces abroad that have committed a range of human rights violations that include torture, sexual assault, and extrajudicial killings in the course of anti-poaching efforts,” the two-paragraph letter reads. “Despite the importance of protecting wildlife and endangered species from extinction, the United States must not be party to violations of basic human rights.”

The request comes a month after committee leaders sent a letter urging the Government Accountability Office to look into the issue. The federal watchdog indicated it will take it up but has not started the review, said committee spokesman Adam Sarvana.