This roundup of claims has been compiled by Full Fact, the UK’s largest fact checking charity working to find, expose and counter the harms of bad information.

Hoax posts about serial killers, stabbings, injured dogs and other alarming or emotive stories are still rife in local Facebook community groups, 18 months after a major Full Fact investigation exposed the scale of the problem.

Full Fact has identified at least 47 communities across the UK which were the victim of such hoaxes in February. The local Facebook groups affected ranged from those covering big cities such as Belfast, Edinburgh and Manchester to those for towns including Banbury, Melton Mowbray and Oldham.

Our August 2023 investigation into this problem found hoax posts were inundating community Facebook groups across the UK with stories about alarming events supposedly taking place in the local area.

We found that once hoax posts had generated engagement, the author would often edit the post, changing it into something completely different, such as a survey, property listing or advert for a cashback site. In some cases the edited posts used affiliate links (special web links which allow someone to earn a small commission for promoting a product or service).

Other posts never go on to be edited and their false claims remain littered across local Facebook groups, potentially drowning out entirely genuine appeals and requests for help.

Hoax posts are often shared across multiple different Facebook community groups, with only the location quoted in the text changing. Often they make emotive appeals, relating to supposedly unidentified children, elderly people or injured dogs.

But in February, we also debunked several alarmist posts, the kind aimed at terrifying communities rather than generating sympathy.

One such post, variations of which appeared in local Facebook groups in Milton Keynes, the Lake District and Wordsley in the West Midlands, claimed that a “serial killer” was breaking into people’s houses locally, robbing them and shooting them.

Another, shown to residents in Middlesbrough and Brooklands in Greater Manchester, warned a man claiming to be homeless was knocking on people’s doors and had attacked a mother with a knife.

A third, shared in Bradford and in Honiton in Devon, claimed a woman had been found stabbed by a local canal.

All of these claims were false, with local police forces confirming they had no records of any such incidents. The photos used alongside the posts also originated from outside the UK and did not relate to the supposed incidents being reported.

Spotting hoax posts on Facebook isn’t always easy, especially as many people do use the social network to send out entirely legitimate alerts to local communities. In 2023, Full Fact wrote a guide with seven ways to spot if a Facebook post in a local community group is a hoax.

One possible warning sign that a post may be a hoax is that the comments are disabled – this means Facebook users are unable to warn others that the post is not legitimate.

You should also watch out for images which don’t appear to be from the UK, such as pictures of obviously American police cars or petrol stations. And the use of language which doesn’t look like it’s from the UK can be another clue – for example, if the term ‘silver alert’ appears in UK Facebook groups. (Silver alerts are used in the US to notify the public about missing people).

Full Fact has written to Meta, Facebook’s parent company, to raise concerns about the hoax posts problem and ask it to take action. We also approached Meta for comment.