(CNN) -- London detectives have been granted visas to Libya to continue an investigation into the 1984 shooting death of Scotland Yard officer killed outside the Libyan diplomatic offices in London, authorities said Thursday.
Officer Yvonne Fletcher was policing a demonstration outside the Libyan People's Bureau in St. James' Square in April 1984 when a bullet fired from the diplomatic building struck Fletcher in the back and killed her, authorities said.
Ten demonstrators also were injured in the incident, authorities said.
"The investigation has always remained open and the inquiry team within the Counter Terrorism Command remains committed to identifying those people responsible," the Metropolitan Police Service said in a statement.
Investigators have visited Libya several times and met with officials from the Libyan investigative team, including in 2004, 2006 and 2007, authorities said. Fletcher's death is under joint investigation by London and Libyan investigators, London police said.
CNN's Michael Martinez contributed to this report.