To Afghan officials, Tuesday’s attack bore the hallmarks of an operation directed by Pakistan’s military intelligence service, the I.S.I.

“The bomber was sent and guided by the I.S.I.,” Maj. Gen. Tadin Khan, the police chief of Kandahar, said on Thursday.

Though not specifically named by the authorities, the Taliban, many of whose leaders are believed to live in Pakistan, have carried out suicide bombings in southern Afghanistan in the past. Afghan and Western officials have long accused the Pakistani military, particularly its intelligence service, the I.S.I., of providing covert aid and direction to the Taliban as a way to wield influence in Afghanistan.

A spokesman for the Taliban, Zabihullah Mujahid, denied the group’s involvement, saying: “The incident in Kandahar and the killing of any Baluch has nothing to do with us.”

In October, General Khan’s brother, Gen. Abdul Raziq, the powerful police chief of Kandahar, was killed by a teenage infiltrator who authorities said had trained in Pakistan. General Raziq was a staunch critic of Pakistan for harboring Taliban leaders.