London (CNN) -- Libya's prime minister laid a wreath Friday at the spot where a London police officer was killed outside the Libyan diplomatic offices 28 years ago.
The wreath-laying happened a day after London detectives were granted visas to visit Libya to continue their investigation of Yvonne Fletcher's death.
Libyan Prime Minister Abdurrahim El-Keib walked up to the memorial at St. James's Square in central London and laid the white wreath at the spot where Fletcher died, where a marker reads "Here fell WPC Yvonne Fletcher, 17th April 1984."
Fletcher was policing a demonstration outside the Libyan offices when a bullet fired from inside the building struck her in the back and killed her, authorities said.
Ten demonstrators also were injured in the incident, authorities said.
British Prime Minister David Cameron said in a statement Friday that he was pleased that detectives were going to Libya, calling it "a really positive step forward."
London's Metropolitan Police Service said Thursday that the investigation has remained open and that the Counter Terrorism Command wants to find those responsible for Fletcher's death.
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 authorities, London police said.