A car key helps crack a criminal conspiracy to steal luxury car parts, and a torch provides the proof needed to convict a man of violently assaulting a pensioner in a graveyard.

An elderly murderer is convicted after a cat-and-mouse chase with armed police. He had killed a man in a feud over garden clippings. And a fraudster is locked up after using dummy phone handsets to con high-street shops out of tens of thousands of pounds.

A plot to extort thousands of pounds from a casino is foiled by a high-stakes sting operation, and a discarded cigarette butt helps convict a man of indecent assault.

A thief who prowls for victims on social media is locked up, thanks to the sheath of his knife, and a plea for help scrawled on a £10 note puts two kidnappers behind bars.

A spent bullet casing holds the key to bringing two murderers to justice, and a hire car helps track down a thief who has stolen thousands from supermarket tills.

A travel card holds the key to convicting a violent offender after a spate of random stabbings. Police taser the man whilst he brandishes weapons on a public street. Also, a bureau de change receipt helps put a pair of thieves behind bars after they subject their victim to a terrifying ordeal.

A packet of wet wipes helps convict a driver responsible for a deadly hit and run, and a distinctive tracksuit puts a gang of ruthless thieves behind bars.

Stained bank notes hold the key to tracking down a brazen bank robber, and hidden-camera footage from a hi-tech sting operation helps snare a prolific gang of thieves.

A mobile phone hidden in a bundle of clothes helps save a young woman from a forced marriage, and a burnt tea towel helps convict a gang of a callous shooting.

A drug boss is put behind bars thanks to a paper trail from his dodgy property empire, and an observant cashier helps convict a fraudster who is posing as a police officer.

A bloodstained shopping trolley holds the key to solving a vicious assault, and a distinctive pair of curtains puts a phone thief behind bars.

A train ticket and a chance encounter help hunt down a pair of hi-tech international fraudsters, and a bottle of milk seals a case against a violent offender.

An airport hire care helps bring a pair of international hitmen to justice after a private investigator is murdered, and a bottle of Caribbean rum helps convict a prolific burglar.

A discarded cigarette butt gives police the proof they need to find the murderers of a young father shot and killed in broad daylight, and a used match found in a drainpipe identifies the arsonist who burnt a 400-year-old building to the ground.

A yacht is tracked by police as a gang uses it to smuggle deadly weapons into Britain, and a prison phone call helps jail a bank cashier for arranging to steal thousands.