Examining the death of 17-year-old Connor Lyons, whose body was discovered next to a riverbank in Hull by a dog walker. With no obvious injuries, investigators questioned whether this was the result of a tragic accident, suicide, or something more sinister. Detectives were left searching for answers until a social media post led them to suspect foul play.

When 82-year-old Mohammed Saleem is fatally stabbed in Birmingham and a series of explosions targets mosques in the West Midlands, counter terrorism uncovers a hate-fueled campaign. 

When a 72-year-old woman is found dead in her bed, police find DNA evidence linking a suspect. With no confirmed cause of death, they turn to advanced forensics to uncover the truth. 

A father and son are found murdered in South Carolina, shot at point-blank range. DNA found at the crime scene leads investigators to uncover a deadly plot driven by greed. 

Just streets away from the neon lights and fairground rides of Blackpool, police rush to the scene of a fire in an alleyway and make a grim discovery; the burning body of a teenage girl.

She's identified through DNA as missing 16-year-old Sasha Marsden, the brutality of her murder shocks even hardened detectives. Sasha hasn't been seen since being dropped off in the city centre for a new cleaning job at a hotel, but after finding sinister social media messages police discover things aren't what they seem, they're convinced she has fallen prey to a dangerous predator that if not stopped, will strike again.

The killer thinks he can outsmart the police, but forensic experts uncover a trail of hidden evidence to give detectives the advantage.