How did a sewage tank truck packed with explosives penetrate a heavily fortified area of the Afghan capital and carry out the deadliest attack in Kabul since the U.S.-led invasion in 2001?
That is the question angry Afghans want the government to answer, and provide some explanation for the security lapse that resulted in the deaths of at least 90 people and more than 400 wounded.
The May 31 explosion, whose casualties were mainly civilians, including women and children, occurred during the morning rush hour in the district known unofficially as the Green Zone, home to foreign embassies, NATO's headquarters, and the presidential palace
A number of Kabul residents have accused the national-unity government of a major security and intelligence blunder. That has added to mounting pressure on the deeply divided and unpopular government of President Ashraf Ghani, which has faced criticism for its handling of the growing Taliban insurgency.