Could new evidence help Ireland learn who killed Michael Collins?

Historians, film-makers and forensic scientists try to answer question once and for all as centenary nears

It is the shot that a century later still echoes around Ireland as an unanswered question: who killed Michael Collins?

On this much, everyone agrees: a bullet to the head killed the revolutionary leader on 22 August 1922 near Beal na Blath, a village in County Cork, during Ireland's civil war. Who did it, and why, remains a source of controversy and speculation that now bubbles as strong as ever.