"We urge you to expeditiously work with Secretary-General [Antonio] Guterres to appoint an independent, transparent, and comprehensive UN special investigation into the murders of Mr. [Michael] Sharp and Ms. [Zaida] Catalan and ensure that any such inquiry is conducted in collaboration and coordination with other ongoing investigative efforts by relevant national authorities," the ten senators said in their letter to Haley on Friday.
Sharp, a US citizen, and Zaida, a dual citizen of Sweden and Chile, were killed in the Kasai region of the DRC while they were investigating human rights violations.
Haley called for a special investigation into the incident in early June, but no apparent progress has been made in establishing a probe, the senators noted.
"The investigation should move forward as quickly and discreetly as possible — before evidence is destroyed or witnesses cannot be located. We further urge that, once completed, the investigation’s findings be made public," the senators wrote.
The letter was signed by Senators Pat Roberts, Cory Booker, Ed Markey, Jerry Moran, Lisa Murkowski, John Kennedy, Chris Coons, Susan Collins, Richard Durbin and Jeff Merkley.
The humanitarian situation in the Kasai region has sharply deteriorated in recent months, as government security forces battle various militias there.
Around 1.3 million people have been displaced by the ethnic violence.