Prominent Somali businessman Ahmed Nure Awdiini has been shot dead at point-blank range in the capital, Mogadishu, police have said.
More than 100 people have been arrested for questioning over his killing, police said.
Mr Awdiini was the head of the business community in Somalia’s biggest market, Bakara.
African Union and government forces captured the market from the al-Qaeda-linked al-Shabab group last year.
Mogadishu police CID chief Abdullahi Hassan Barise told the BBC Somali Service that gunmen opened fire on Mr Awdiini outside his office in the city.
Mr Awdiini, who had two wives and 14 children, was hit in the chest and died on the spot, he added.
Mr Barise said police would not speculate on the cause of his murder.
More than 100 people have been arrested, as police investigate the killing, he added.
Al-Shabab is fighting to overthrow the government, which is backed by an 18,000-strong AU force.
The militant group has been forced out of most urban areas, including Mogadishu, but still controls much of southern and central Somalia.
It still carries out bombings and assassinations in the capital.
Many criminals gangs and private militias are also active in Mogadishu.