Joseph Kony Uganda war crimes film goes viral

A campaign by US activists to capture alleged Ugandan war criminal Joseph Kony has gone viral on the web.

Invisible Children's half-hour film on the use of child soldiers by Kony's Lord's Resistance Army has been viewed nearly 10 million times on YouTube.

The group aims to bring Kony to justice at the International Criminal Court, where he is charged with crimes against humanity.

Christian d'Ippolito is from viral video experts Unruly Media. He explained to the BBC how the viral campaign gathered momentum.