The families of two British tourists killed by a teenager in Florida branded him “evil” as he was handed two life sentences.

James Kouzaris, 24, and James Cooper, 25, were gunned down by Shawn Tyson after they drunkenly walked into a rundown public housing estate in Sarasota in the early hours of April 16 last year.

The killer, who sports a tattoo of the word “savage” on his chest, will spend his life in prison without parole after being convicted of two counts of first degree murder. Tyson, who has just turned 17, avoided the death penalty because of his age.

The families of the two friends expressed anger at the fact he was released from juvenile detention a day before he killed them. Tyson had been arrested on April 7 for shooting at a car, but because of an administrative error was released on April 15 to the care of his mother. Less than 24 hours later he had shot Mr Cooper, a tennis coach from Hampton Lucy, near Warwick, and Mr Kouzaris, a town planner from Northampton.

In a statement, the families said: “It is a fact that we were given a life sentence when our sons were so brutally and needlessly taken from us. Ours is a life sentence, with no chance of parole from a broken heart, and a shattered soul. The agonising and searing pain we have experienced will continue until our sentence is at an end. The evil of the killer is one thing, but the fact is, he would not have been on the streets had instructions to keep him incarcerated been passed from one judge to another.”

The court heard emotional statements from two friends, Joe Hallett and Paul Davies, and saw tribute videos made in memory of the two victims.

Prosecutor Karen Fraivillig read a statement from Mr Cooper’s parents Stan and Sandy which said: “Anyone who has lost a child will know there are no words which can express the despair, disbelief and desolation. We will miss him every minute of every day in a home that now feels empty.”

In a video played to the court, Mr Kouzaris’s father Pete, alongside wife Hazel, said: “We have suffered and continue to suffer,” and added that said his son had been “needlessly taken from us in a moment of madness”.

It took the jury just under two hours to convict Tyson of two counts of murder in the first degree. If he had been 18 when he committed the murders he could have been given the death penalty.

When Mr Kouzaris and Mr Cooper drunkenly walked into a housing project known as The Court, they were confronted by Tyson, who tried to rob them. When they had no money, he told them: “Well, since you ain’t got no money, I got something for your ass.” The men pleaded to go home, saying they were drunk, but the teenager, then 16, shot one then the other. When they were found, both still had their wallets and cash – Mr Cooper had 63.45 dollars and Mr Kouzaris had 62.05 dollars.