Wali Karzai had survived attempts on his life before, most recently in 2009.
A controversial politician, some saw him as a defender of Pashtun rights.
Critics said he was a warlord mired in corruption and was openly involved in drugs trade and had a personal militia at his disposal.
President Karzai repeatedly defended him denouncing accusations that his brother was involved in criminal activities.
Wali Karzai came into limelight after the Taleban executed in October 2001 Abdul Haq, the veteran Afghan resistance commander, who fought against the Soviets and Afghan communists during the Soviet-Afghan war.
Abdul Haq's execution opened several bonanzas for Popalzai brothers - the Karzais, who lived in Quetta during the Taleban rule in Kabul in the late 90s.
Execution of Abdul Haq made Wali Karzai the most sought-after fixer in Quetta. He was the fixer, scheduling officer and top front-man of Hamid Karzai.
Wali Karzai used to tell President Karzai, "Give me Kandahar and I will finish the Taleban."
Many people in Chaman, a border town in Balochistan, say, "Wali Karzai had backchannel links with Mullah Omar's men in Kandahar."
A post-graduate from the US, Wali Karazi strongly followed an American philosophy, "What money cannot buy, more money can." For easy money he opted to head drugs trade and receive kickbacks from every contractor employed either by the Afghan government or the US -led ISAF in Afghanistan for the implementation of Bonn and Tokyo declarations promising 'Reconstruction' of the country.
Wali Karzai had had frequent meetings with the former US top commander in Afghanistan, Gen. David Petraeus.
Mindful of his personal security Wali Karzai had employed over 500 bodyguards.
