Tanzanian security organs are working round the clock to solve the puzzle surrounding the dramatic abduction of billionaire Mohammed Dewji in Dar es Salaam early Thursday morning.
Dar es Salaam Special Zone police commander Lazaro Mambosasa said armed kidnappers whom he described as "white men," suggesting they were foreigners, grabbed Mr Dewji, Tanzania's youngest billionaire, at the Colosseum Hotel at dawn as he headed into a gymnasium.
Sources close to the investigation told The EastAfrican that they suspected the hand of foreigners working with locals, but the motive of the kidnap was yet to be determined.
By midday Friday, 30 people were reported to have been held by the police for questioning in connection with the crime. Mr Mambosasa said the number was likely to rise as investigations continued.
He did not name those in police custody, but on Thursday he had indicated that the initial arrests involved security staff of the Colosseum Hotel: five guards from G1 Security and the security manager.
The police also visited the Yacht Club on the shores of the Indian Ocean, where Mr Dewji is believed to a member, to study CCTV footage. The management, however, said he did not go there on the day he disappeared.
Mr Dewji was abducted as he went into the exclusive Colosseum Hotel and Fitness Club in Oyster Bay, an affluent neighbourhood in Dar.
Eyewitnesses say masked men arrived in two vehicles and parked outside the hotel before Mr Dewji got there around 5am.
A taxi driver said that as Mr Dewji drove in, two white men got out, seized him, forced him into one of the cars and sped away while shooting in the air. The Dar es Salaam police chief said footage retrieved from the hotel's security cameras was not clear.
What is known is that Mr Dewji drove himself to the gym from his residence, on Laibon Street, Oyster Bay. Information gathered from a Colosseum Hotel staffer has it that the businessman usually drives himself to the gym for routine morning workout.
Mr Dewji is the owner of Mohamed Enterprises Tanzania Ltd (MeTL), a conglomerate that has a footprint in at least five African countries.
He deals in textiles, beverages, edible oils and cereals.
For decades Mr Dewji has been involved in sisal plantations that he acquired from the government.
Forbes magazine estimates his net worth at $1.5 billion.
He is a major shareholder of Tanzania's premier league champions, Simba Sports Club, with a 49 per cent stake. Simba is one of Africa's oldest football clubs. In the early 2000s, Mr Dewji was one of the top sponsors of Simba during which time the club reached the last eight of the African Champions League in 2003.
He served as a Member of Parliament for Singida Urban constituency between 2005 and 2015. He is popular for providing clean water across the constituency and constructing Chama cha Mapinduzi offices across Singida Region.
Mr Dewji also runs the Mo Dewji Foundation, which provides scholarships to outstanding high school graduates seeking further education.
-Additional reporting by Florian Kaijage and Emmanuel Onyango.