A taxi driver has been arrested over the murder of British diplomat Rebecca Dykes in Lebanon, police in Beirut have confirmed.
An official said the Lebanese suspect confessed that he had killed the 30-year-old, whose body was found early on Saturday by the side of the Metn highway, east of the Lebanese capital.
Police are describing it as a "criminal act" but say it was not politically motivated.
Earlier, a local forensics officer told the Associated Press news agency that Ms Dykes, who worked at the UK embassy in the city, was strangled with a rope.
The unnamed official added that authorities were investigating the exact cause of her death and whether she was sexually assaulted, with Lebanese media having reported that choke marks were found on her neck and that she had been raped. She also had a piece of string tied around her neck.
Local media reported that Ms Dykes - who had been due to fly home for Christmas on Saturday - had been out in the Gemmayzeh area of Beirut on Friday night with work colleagues, and left a bar on her own at around midnight.
A family spokesman said they were "devastated by the loss of our beloved Rebecca".
"We are doing all we can to understand what happened," he said.
According to Ms Dykes' LinkedIn profile, she had been working as a programme and policy manager for the Department for International Development (DfID) on the UK government's Conflict, Stability and Security Fund (CSSF) programme in Lebanon.
A DfID spokesman said: "Our thoughts are with Becky's family and friends at this very upsetting time."
"There is now a police investigation and the FCO (Foreign Office) is providing consular support to Becky's family and working with the local authorities."
Our thoughts are with the family and friends of Becky Dykes at this very upsetting time.
— DFID (@DFID_UK) December 17, 2017
The UK Foreign Office has said it is in contact with authorities in Lebanon.
"Following the death of a British woman in Beirut, we are providing support to the family," a spokesman said.
"We remain in close contact with local authorities. Our thoughts are with the family at this difficult time."
The British ambassador to Lebanon, Hugo Shorter, tweeted his condolences saying the whole embassy was "deeply shocked" and "saddened".
He said the embassy was "working closely with Lebanese authorities who are conducting police investigation".
The whole embassy is deeply shocked, saddened by this news. My thoughts are with Becky’s family, friends and colleagues for their tragic loss. We're providing consular support to her family & working very closely with Lebanese authorities who are conducting police investigation.
— Hugo Shorter (@HugoShorter) December 17, 2017