Both clips show US soldiers shooting apparently unarmed and injured Iraqis. According to military and legal experts interviewed by the Panorama programme, they show US troops breaking international law by shooting unarmed people.
As reported by this site on 14 January, a video of footage from a US Apache helicopter had been widely circulated on the web following its broadcast on ABC News. Aerial footage shows Iraqis apparently abandoning something - which soldiers assumed to be a weapon - and running for cover.
Soldiers receive instructions to 'shoot it' and kill all three men, including one wounded person already lying on the ground.
A second incident was recorded in April 2003 by a CNN crew and broadcast in October that year. Soldiers are seen shooting unarmed and seriously injured Iraqis during a search of an industrial area. Immediately after the shooting, one soldier describes the situation as 'awesome' and says he 'wants to do it all over again'.
During the Panorama documentary, US Viet Nam veteran General Robert G Gard, describes both events as 'inexcusable murders'. Professor Stefan Oeter, an expert in international law, confirms that the shooting of a wounded person is a war crime.
Panorama producer Volker Steinhoff began investigating the two stories after an email tip from a colleague.
"Without the internet, I might not have done the story since watching the video is the central argument for the story."
Mr Steinhoff told dotJournalism he was surprised that neither story had been pursued by the mainstream media.
"It's my impression that CNN and ABC deliberately hid the story - ABC never mentioned the crucial point. The US mainstream media have been extremely unco-operative.
"This issue of shooting wounded people - a possible war crime - hasn't had enough public attention either in Germany or the US."
The programme will be broadcast on German channel ARD at 20.15, central European time, on 26 February.
The full transcript of the Panorama documentary will be available online from noon on 27 February and the two video files will be on the ARD site for Friday only, subject to final permission from CNN.
The US Ministry of Defence has refused to comment on the Panorama investigation.
CNN video downloads:
ABC Apache video downloads:
Free daily newsletter
- Save Journalism Project launches fundraiser to pay laid-off US reporters $2-a-word to write about media job cuts
- New resource helps US newsrooms address the 'dramatic decline of local journalism'
- Behind the BBC's interactive 'The rise of the Islamic State'
- 2003-2013: A decade of change for journalism in Iraq
- The changing face of journalism in Iraq