24 Hours In Police Custody to show how anonymous online messages escalated

Detective Emily Richardson, of Cambridgeshire Police, is faced with the challenge of trying to work out what is really going on after both Megan and Daniel separately report a series of harassing phone calls and death threats from an unknown third party.

The online harassment then moves from virtual threats to invasions into their personal lives and work.

After the police receive the first of dozens of hoax calls accusing the couple of murder, firearms officers are dispatched in the middle of the night to investigate.

The police fail to find a body after each tip-off but the calls keep coming.

Ms Richardson tells the documentary: “Normally, when you get given an investigation, you have a suspect.

“Most people know who it is that they’re accusing of a crime so it adds a whole other layer, that you’re dealing with an unknown, you don’t know who they are, you don’t know what they’re capable of.”

She added: “I suppose it’s the boy who cried wolf, you know, they could’ve reported a hoax call three times, the next one could be real, you never know.”

One call saw five response officers, an armed vehicle and three ambulances deployed to reports of a man stabbed, but after searching the property no sign of a stabbing is found.

The pair tell police they have no idea who could be behind it.

Ms Richardson said: “With all phone work there’s limitations, especially for a case like this where a lot of the crime has been committed on social media, but there’s a lot of things in the background that we can do that perhaps people aren’t aware of.”

Then an encounter with a specialist sergeant, Tracy Williams, makes Ms Richardson think about the investigation in a new light.

24 Hours In Police Custody: The Murder Messages airs on Monday at 9pm on Channel 4.