A taxi driver suspected of killing British embassy employee Rebecca Dykes in Lebanon is being questioned by police, a security source briefed on the matter told CNN.

The man was taken into custody Monday morning, according to the source. Investigations revealed that the suspect picked Dykes up from a bar in his taxi and drove her to a mountainside motorway where he sexually assaulted and strangled her with a rope, the source said.

The suspects' bodily fluids were found on Dykes' body, the source added.

The UK Foreign and Commonwealth Office confirmed to CNN that Dykes was an employee at the UK Department of International Development at the UK Embassy in Beirut.

She was last seen leaving a bar named "Demo" off of the Gemmayze Street, a popular nightlife spot near central Beirut on Friday night.

Dykes' body was found in a ditch along a mountain highway close to the outskirts of the Lebanese capital on Saturday morning, the source said. The poorly-lit, desolate highway is flanked by forests and connects Beirut with several mountain villages.

Hugo Shorter, British Ambassador to Lebanon, tweeted, "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."