Investigators inspect the scene, where Ethiopia's Grand Renaissance Dam Project Manager Simegnew Bekele was found dead in his car in Addis Ababa, Ethiopia

The project manager of a $4 billion Ethiopian dam being built on the river Nile has been found dead, a Reuters photographer said on Thursday.

The photographer observed blood stains along an arm rest inside his car - a Toyota Landcruiser - before an ambulance took away the corpse. State media also reported the death, without disclosing the cause.

“Engineer Simegnew Bekele was found dead in his car this morning in Meskel Square. His body has been taken to hospital for an autopsy,” Fana Broadcasting Corporation said, referring to an area in the center of the capital.

Simegnew project-managed the Grand Renaissance Dam, centerpiece of Ethiopia’s bid to become Africa’s biggest power exporter. The country plans to spend some $12 billion on harnessing its rivers for hydro power in the next two decades.

But talks with Egypt - whose main source of water is the Nile - and Sudan on disagreements over its impact on the river have been deadlocked for months.

A bone of contention for both Ethiopia and Egypt is the speed at which the dam’s reservoir would be filled.

In June, the leaders of Ethiopia and Egypt vowed to iron out their differences peacefully. They also agreed to take steps to put into effect an agreement - which also includes Sudan - to set up a fund for investing in infrastructure in the three countries.