Ahmed Wali Karzai was conducting business in his normal fashion on Tuesday morning, holding court as 60 to 70 people filled the rooms of his large residence that also served as his office in central Kandahar, when one of his most faithful commanders asked to speak to him alone and then shot him at point-blank range. The head of the elected provincial council, Mr. Karzai wielded power far beyond that office, both because he was a half brother to the president, Hamid Karzai, and because he had amassed great wealth and power over business, security and administrative affairs in Kandahar Province and much of southern Afghanistan. Every day his office was filled with petitioners, provincial officials, and tribal and family friends who came to seek his advice and support on business matters, political dealings and tribal disputes. On Tuesday morning he sat for half an hour with Mir Wali, a former legislator from neighboring Helmand Province, who is one of those contesting recent parliamentary election results. Then a fellow provincial councilor, Haji Agha Lalai, entered and requested five minutes of Mr. Karzai’s time. The two descended to the first floor and sat for a few minutes before an old man from the city requested a hearing. Mr. Karzai moved into a room with the old man, and it was then that a commander, Sardar Muhammad, 40, asked to see Mr. Karzai alone. He was carrying a file and wanted Mr. Karzai to look at the information inside, said Haji Sayed Jan, a close colleague who is considered Mr. Karzai’s deputy on the provincial council.