16-year-old youth has been charged with murdering two British tourists who were shot dead in Florida last month.

Shawn Tyson will be tried as an adult for first-degree murder after the deaths of James Kouzaris, 24, and 25-year-old James Cooper, Sarasota Police said.

If Tyson is convicted, he will be sentenced to life in prison without the possibility of parole.

Mr Kouzaris, of Northampton, and Mr Cooper, from Hampton Lucy near Warwick, were gunned down in a rundown Sarasota neighbourhood on April 16.

The friends had been on holiday with Mr Cooper's parents in Longboat Key, about 12 miles from the murder scene.

CCTV images show the pair in bars in downtown Sarasota just 90 minutes before they were murdered.

It is still not known how or why they travelled to the area where they were killed, which was 20 blocks away.

Tyson had reportedly been released from police custody hours before their deaths, despite a judge raising concerns that he posed a danger to the community.

Earlier in the month the teenager had appeared in court on charges that he fired gun shots into an occupied car in an unrelated crime.

The evidence against Tyson in the murder case has not been released, after a judge sealed the court document in which it is detailed.

Authorities say witnesses could be in danger and the investigation damaged if the information is made public.