Maxim Grigoriev of the "Foundation for the Study of Democracy", discussed this and other findings gleaned from interviews with numerous individuals, including former terrorists, in Syria, during a video-taped presentation entitled, "Roundtable Discussion on the Middle East Issues: Activities of the White Helmets Organization in Syria" under UN auspices.
One interview subject, Omar Al-Mustafa who wanted to be a White Helmet but wasn't accepted because he wasn't al Nusra Front (al Qaeda) recounted the following:
"People evacuated by the White Helmets often did not come back alive. For example, a person receives a minor injury, is rescued, evacuated, and then brought back with their stomach cut open and with their internal organs missing. I heard that a little girl was injured. They took her to Turkey and brought back in three days, dead and with no internal organs. People were scared. When someone got injured, they were afraid to call the White Helmets and ask for help."
Grigoriev's findings, presented at the U.N, are consistent with previous on-the ground investigations, including those of pioneering investigative journalist Vanessa Beeley (also featured in the Roundtable investigation), and Prof. Tim Anderson. In October, 2017, locals told Prof. Tim Anderson that the building pictured below had been used for organ trafficking.
Additionally, the Director-General of Syria's Coroner's Office, Houssein Noufel, reported in November, 2016, that body organs from 15,000 Syrians were sold over the course of six years. 
A litany of crimes committed by the White Helmets is documented in the video below.
Equally disturbing, however, is that Western agencies, including Amnesty International, Syrian Observatory for Human Rights, and Western media, use the White Helmets as sources for their stories.
A U.K document entitled, "Syria Resilience CSSF Programme Study" states, in reference to the White Helmets, which it names Syrian Civil Defence (SCD),
"In addition to service delivery, SCD provide an invaluable reporting and advocacy role, being nominated again this year for the Nobel Peace Prize. Human Rights Watch and Amnesty International have stated that SCD are their most routinely reliable source for reporting. Throughout the bombardment by Russia since September 2015, SCD has provided essential corroboration that strikes were not targeting Da'esh but moderate opposition entities. This has provided confidence to statements made by UK and other international leaders made in condemnation of Russian actions."
Amply documented, the "news" that the White Helmets report to Amnesty, SOHR, and myriad government sources, consists of fake news and staged rescues. Consider these screen grabs from the above video on UNWeb TV: