Detectives reveal the methods used to solve some of Britain’s most heinous crimes. How do police officers locate perpetrators who are using the anonymity of the dark web? In this episode, investigators reveal the methods used to trap a blackmailer buying personal details online for extortion purposes. Plus, the police investigation that smashed a gang of house thieves terrorizing Welsh towns.

Britain’s top detectives have to travel far and wide to apprehend some of the worst offenders. This true crime documentary reveals how the National Crime Agency bust an international network that were smuggling people in and out of the UK using a fleet of taxis and trucks. And one determined detective sets off on a Europe-wide chase to arrest a gang of thieves terrorizing his community.

Internet swindling is an increasingly problematic offence. This true crime documentary follows one detective trying to catch a romance fraudster who stole nearly £250K from victims while posing as a wealthy property developer. Also, there’s a jaw-dropping rooftop chase as officers try to arrest a shameless courier fraud gang who stop at nothing to con their victims out of their cash.

Sometimes, even once the criminals have been convicted, the crimes continue. Detectives investigate a prison worker who smuggled contraband into jail for her lover, which leads to the discovery of the biggest prison smuggling conspiracy in UK history. Also, there’s a race against time to find the person responsible for the chilling stabbing of a homeless man on the streets of London.

We put our utmost trust in those looking after our health. But sometimes that’s not enough. This true crime documentary follows one determined detective as they investigate healthcare workers who were unlawfully drugging patients on a hospital stroke ward, and then bragging about it. And then witness a dramatic arrest as a man responsible for stabbing a doctor on his doorstep is confronted.

A mobile phone is discovered at the scene of a minor car crash. This seemingly innocuous item leads detectives to unearth a huge drugs conspiracy connected to the device. And this true crime documentary also investigates the murder of Tati Rodgers and learns how her cold-hearted killer was eventually caught, thanks to an elaborate double bluff set by the Welsh police.

Some criminal cases are open and shut. Others are long, complicated and fraught with danger. This true crime documentary follows a determined group of detectives attempting to take down a gang selling industrial amounts of cocaine and laundering their profits through multiple cryptocurrency accounts. Plus, officers try to track down a legal professional stealing his clients' money.

When a man confesses that a woman is lying dead in his house, police must establish whether she died as a result of an accident or if she was murdered. Also, detectives and forensic experts describe how killer John Cooper was finally found guilty of murder, decades after he committed his crimes. Advances in forensic technology finally helped police crack these two infamous double murder cases.

There’s a cat-and-mouse chase as detectives try to bust a gang who enrolled at a Welsh university in order to sell drugs to students. Plus, why did a man who was attacked with a machete refuse to cooperate with the police? After a shooting, detectives finally connect the crimes. But it takes a visit to a hospital x-ray department to finally find the unusual hiding place of the gun.

A violent burglar ties up a homeowner during a home invasion. But, as this true crime documentary reveals, it would take a team of dedicated officers two and a half years before they could finally catch him. Plus, there’s the case of a bodybuilder selling potentially deadly diet pills. Can detectives track him down before someone is seriously injured or killed?