Sri Lanka's Killing Fields: Jon Snow presents a forensic investigation into the final weeks of the quarter-century-long civil war between the government of Sri Lanka and the secessionist rebels, the Tamil Tigers. With disturbing and distressing descriptions and film of executions, atrocities and the shelling of civilians the programme features devastating new video evidence of war crimes - some of the most horrific footage Channel 4 has ever broadcast. Captured on mobile phones, both by Tamils under attack and government soldiers as war trophies, the disturbing footage shows: the extra-judicial executions of prisoners; the aftermath of targeted shelling of civilian camps; and dead female Tamil fighters who appear to have been raped or sexually assaulted, abused and murdered. The film is made and broadcast as UN Secretary-General Ban Ki-moon faces growing criticism for refusing to launch an investigation into 'credible allegations' that Sri Lankan forces committed war crimes during the closing weeks of the bloody conflict with the Tamil Tigers.