Detectives in Florida are trying to establish what led two British holidaymakers from a “night on the town” in the centre of Sarasota to a run-down, crime-ridden area of the city where they were shot dead – allegedly by a 16-year-old boy – in the early hours of Saturday.

Police Chief Mikal Holloway said investigators believe James M. Cooper, 25, and James Thomas Kouzaris, 24, had gone to the Newtown neighbourhood voluntarily before they were killed early Saturday.

The 16-year-old suspect was arrested about 24 hours later, but police won’t say what evidence led to them to the teen.

The boy, who police have yet to identify, was being held in a juvenile facility. His mother and a public defender represented him in court. Prosecutors have until May 8 to decide whether to charge him as an adult.

Officers responded to an emergency call at about 3am Saturday reporting a man had collapsed on the street and was bleeding. The other man was discovered lying across the street.

“The investigation is ongoing, and we do believe there are more facts that will be forthcoming that will help us with the investigation,” Holloway said at a news conference.

Holloway said police “have their suspicions” as to why the men were in the Newtown neighbourhood north of downtown, “but at this time, it would be unfair to state those.”

The area where the men were killed is made up of low-slung cinder-block apartment buildings and is far removed from the beaches and other tourist attractions. It is known for its drug trade and crime, although officials say the crime rate there has dipped in recent years.

Cooper and Kouzaris had recently graduated from college and were on vacation in the United States, Holloway said. Multiple British press reports and Kouzaris’ Facebook page indicated the two had attended the University of Sheffield together.

Sarasota Mayor Kelly Kirschner said residents and visitors to Sarasota should expect to be safe in any neighborhood at any time of the day or night.

“It’s a gut check for us as a community, with what we’re doing and how we’re dealing with the challenges we face, particularly in (that neighbourhood),” Kirschner said of the city’s first slayings of 2011.