In an attempt to find the killer of WPC Yvonne Fletcher, and the person who attempted to kill 10 anti-Gaddafi protestors in London 30 years ago, the Met is targeting Facebook users based in the UK and 10 other countries in North Africa and the Middle East who they think may hold information vital to the case.
The paid Facebook advert was launched on Thursday, 19 November, and will be promoted until 29 November. The post, which is written in Arabic, will be targeted at men and women aged 35 years and older, and could reach up to seven million people, the Met said.
The Facebook appeal is running alongside a traditional media appeal, which was launched at a press briefing at New Scotland Yard with UK and global media in attendance.
The Met's head of media Ed Stearns said: "The traditional media are hugely important and we get fantastic results through engaging them in our appeals as we did with our briefing yesterday. However, Facebook adverts are giving us fantastic new opportunities to target specific groups, communities and people who we may not otherwise reach through traditional means.
"This appeal will reach people in countries where society has broken down to such an extent that they can't access mainstream media. It means we can get to a group of people in a direct and targeted way - people who might not have otherwise seen our appeal on news coverage."
Stearns also told PRWeek that the Met had previously used geographically targeted Facebook posts to reach people in specific areas of Portugal who might have known about the disappearance of Madeleine McCann, and that it can target people who have indicated they attended a particular nightclub or venue when a crime has taken place there.