A 19-year-old man who committed three knifepoint robberies and one attempted robbery has been sentenced to five years and four months in prison.

Tommie Sweeney, of Gildea Close, Hatch End, appeared before St Albans Crown Court on Wednesday after pleading guilty to all four offences which occurred in Watford in July 2017.

The court previously heard how Sweeney – who was 17 at the time – and his associates targeted four teenagers in Cassiobury Park in the early hours of July 28.

The victims, a group of 17-year-old boys, were attacked as they made their way home from a music event at Watford Colosseum.

They were threatened by a gang of young men wearing balaclavas who attempted to rob them at knifepoint. The first victim was able to escape before they stole anything from him. He called police who immediately attended the scene.

The second, third and fourth victims were forced to hand over their property – including smartphones, wallets, cash, bank cards and clothing – to the gang, who threatened them with knives and in some cases, physically assaulted them.

Three of the victims were also sprayed in the face with a substance later confirmed similar to pepper spray.

Detectives from the Watford Local Crime Unit investigated and later that day two balaclavas and a spray can were found in nearby Park Avenue.

Forensic tests showed DNA from one of the balaclavas matched that of Tommie Sweeney and he was arrested. His mobile phone was seized and after officers downloaded the material, they found a photo of Sweeney inside The Colosseum on the same night of the robberies.

He was later summoned to court to answer three charges of robbery and one charge of attempted robbery, all of which he pleaded guilty to.

Detective Sergeant Ian Siggery, from the Watford Local Crime Unit, said: “Sweeney callously targeted his peers as they all left a music concert and it was a frightening ordeal for all of the victims, who feared for their lives after being assaulted and threatened with weapons.

“I hope Sweeney’s prison sentence brings them a small sense of comfort which will enable them to gain closure and help them move forward. I also want this to serve as a warning to those who choose to commit robberies against innocent members of the public in Watford. We will investigate and we will bring you to justice.

“I also want to commend the excellent work of dDetective Constable Andrew Metselaar, whose dedication and determination is the sole reason we have secured this result for the victims. The standard of his investigation was second to none and prior to the sentencing, he received a letter of thanks from one of the victims who praised his ‘hard work and continued support’. Well done, DC Metselaar.”