Cape Town police are working on possible leads following the murder of Irish charity worker John Curran at a high-security residential complex in the CBD this week.
John Curran, 60, had recently finished a two-year contract as a director of education for Mellon Educate in South Africa.
"I know our many volunteers and supporters will be very sad to hear this tragic news. John was much loved by everyone who met him and especially by the thousands of children he helped during his time with Mellon Educate," said the charity in a statement.
"We are assisting his family in every way we can and your warm wishes of empathy are sincerely appreciated."
The charity said in its statement that Curran was killed during a robbery.
Police spokesperson Sergeant Noloyiso Rwexana said officers responded to a complaint at the building at 09:25 on Wednesday.
Manhattan Place, where his body was found, is opposite the Western Cape headquarters of the National Prosecuting Authority and close to several small eateries, bars and shops.
It is also near the historic Bo-Kaap village and is close to the Hilton Hotel, and the area is bristling with CCTV cameras.
Rwexana said when the officers arrived they found Curran in a pool of blood.
"The victim had open wounds to his head and face," said Rwexana, adding that it still had to be confirmed that he was stabbed.
"Circumstances surrounding this incident are under investigation with no arrests so far. Police detectives are following up on possible leads."
A neighbour tweeted:
The stylish building has a concierge and controlled access.
Its unit's owner said she did not want to comment.
The Irish Times reported that Curran took early retirement in 2005.
He was a founding principal of Good Shepherd national school at Churchtown in Dublin and was also a founding member of the Irish Primary Principals' Network.
He served on its executive committee from 2000 to 2007 and was public relations officer from 2005 to 2009.
According to its website, Mellon Educate South Africa has about 22 000 volunteers and, in conjunction with the South African government, has built houses for 125 000 homeless people in South Africa's poorest townships.
"This was only possible because ordinary people took selfless action to do something truly extraordinary, lend a helping hand on our annual 'building blitz' in South Africa," the charity says on the website.
Its other work includes helping build playgrounds, literacy training for parents to help children with literacy development at home, book quizzes and promoting recycling among school children.