DAR ES SALAAM (Reuters) - Africa’s youngest billionaire, snatched a week ago off the street outside a luxury hotel in Tanzania, was kidnapped in a car that had arrived from “a neighboring country”, police said on Friday.

Police said they had identified the car’s owner and driver, although they declined to identify which country the car had come from, saying to do so might cause diplomatic conflict.

Mohammed Dewji, 43-year-old CEO of the METL Group family conglomerate, was seized as he arrived for a morning workout in Tanzania’s commercial capital Dar es Salaam last week. Forbes estimates his net worth as $1.5 billion, making him Africa’s 17th richest man and its youngest billionaire.

His family have offered a reward of 1 billion Tanzania shillings ($440,000) for information leading to his release.

Police Inspector General Simon Sirro told reporters in Dar es Salaam that the movements of the car used to seize Dewji had been traced on footage obtained from security cameras before it went out of view while still within Dar es Salaam.

“We have got the information on the car owner and the nationality, the driver who was driving it and our people at Interpol are working on it,” he said. Interpol is an international body that circulates requests from police forces for cooperation from police in other countries.

Police were also conducting a house-to-house search for the kidnapped businessman, Sirro said.

Tanzania’s neighbors include Kenya, Uganda, Rwanda, Burundi, Democratic Republic of Congo, Zambia, Malawi and Mozambique.

METL Group is involved in a diverse range of manufacturing, farming, transport, infrastructure, agroprocessing and telecoms businesses spanning 11 African countries.