One year since U.S. commandos flew into the Pakistani army town of Abbottabad and killed Osama bin Laden, Islamabad has failed to answer tough questions over whether its security forces were protecting the world’s most wanted terrorist. Partly as a result, fallout from the raid still poisons relations between Washington and Pakistan, where anti-American sentiment, support for Islamist extremism and anger at the violation of sovereignty in the operation can be summed up by a Twitter hashtag doing the rounds: 02MayBlackDay.

The Pakistani government initially welcomed the raid that killed bin Laden in his three-story compound, but within hours the mood changed as it became clear that Pakistan’s army was cut out of the operation. Any discussions over how bin Laden managed to stay undetected in Pakistan were drowned out in anger at what the army portrayed as a treacherous act by a supposed ally.

That bin Laden was living with his family near Pakistan’s version of West Point—not in a cave in the mountains as many had guessed—raised eyebrows in the West. The Pakistani army was already accused of playing both sides in the campaign against militancy, providing some support against al-Qaida but keeping the Afghan Taliban as strategic allies.

A week after the raid, President Barack Obama said bin Laden had a “support network” in Pakistan and the country must investigate how he evaded capture. Pakistan responded by announcing the formation of a committee to investigate bin Laden’s presence in Pakistan as well as the circumstances surrounding the U.S. raid.

Soon after it began its work, the head of the committee said he was sure that security forces were not hiding bin Laden.… Last week, committee spokesman retired Col. Mohammad Irfan Naziri said its findings were being written up but they might not be released.…

The public line of the Obama administration is that no evidence has emerged to suggest bin Laden had high-level help inside Pakistan. Pakistan’s Inter-Service Intelligence agency said bin Laden’s long and comfortable existence in the country was an “intelligence failure.” But suspicions have increased following recent disclosures by one of bin Laden’s wives in a police interrogation report that the al-Qaida leader lived in five houses while on the run and fathered four children, two of whom were born in Pakistani government hospitals.…

Since the raid, Pakistan has tried to close one of the most notorious chapters in its history. The three-story compound in Abbottabad that housed bin Laden for six years was razed by bulldozers in a surprise, nighttime operation. Just last week, his three wives and 11 daughters, children and grandchildren were deported to Saudi Arabia; their side of the story is unlikely to be told anytime soon.…

After the raid, [Pakistan’s] generals retaliated by kicking out U.S. special forces trainers operating close to the Afghan border, cutting intelligence cooperation with the CIA and restricting the travel of foreign diplomats and aid workers. Authorities arrested a Pakistani doctor who assisted America in tracking down bin Laden. The doctor remains in detention, facing possible treason charges. The country has made not made public the arrests of anyone connected to bin Laden’s time on the run.…

Even before the raid, anti-American sentiment was so rampant in Pakistan that anyone who opposed Washington was lauded by many sections of society.… Despite reservations about Pakistan’s commitment to U.S. goals in Afghanistan and doubts over how bin Laden managed to evade capture for so long, the Obama administration feels it has little choice but to ally itself with the country. Pakistan has nuclear weapons.…