Enraged supporters took to the streets in cities across the country and buildings belonging to Pakistan's powerful military became the target - a shock to the institution widely known locally as the establishment.

"When he was arrested, our hearts sank. We were crying and didn't know what to do," said Hasan, who cycled to a central market in Lahore where Khan's Pakistan Tehreek-e-Insaf (PTI) party had often gathered.

The residence of a lieutenant general in the city had already been set ablaze by then.

On the streets of the capital Islamabad, where Khan was arrested, protesters pulled down street signs, lit fires and threw stones. Scores of military monuments were vandalised.

The military, which has long held sway over governance in the Muslim majority country, swiftly labelled 9 May 2023 a "Black Day". They have also described the protests as an "attack on the army".

One year on, many supporters of the former cricket star are still reeling from the physical and emotional wounds of the day's events.

Hasan was among hundreds arrested for their involvement in the protests. Many of them told BBC Urdu they took to the streets "peacefully" and were not involved in the violence, but were nevertheless held without due process and mistreated while in detention.

Hasan said he joined the protests "because I felt that what happened to Imran Khan was wrong... We were telling the police, 'Today, you have crossed the red line', he said.

"Many Pakistanis have an emotional connection with Khan Sahib," he said, using a local term or respect. "He is like a brother, like a father, to us."

Abrar, another supporter who took to the streets after Khan's arrest, recalled that he left his house in Lahore "immediately" after seeing footage of Khan's arrest last May, as he felt his "leader should not have been humiliated in this way".

Khan is a cricketing icon in a country where the sport enjoys almost fanatical support. He brought glory to the country as captain when he led the national team to World Cup victory in 1992. Many Pakistanis have grown up idolising him.

But critics argue that Mr Khan had the backing of the army during his rise to power, an allegation both sides reject. The military has heavily influenced Pakistan for most of its existence and is a crucial behind-the-scenes player in the country's politics.

He was elected PM in July 2018 but ousted in a parliamentary vote of no-confidence four years later. Shortly before general elections this February he was given several criminal convictions, barring him from standing. He is battling scores of legal cases, including charges for corruption and terrorism, but continues to be a powerful force dividing Pakistan.

During the February elections, his party, which had been denied its election symbol and a united platform, was forced to run candidates as independents, who then emerged as the single largest bloc in a shock result. However, they fell short of the majority needed to form a government.

At least 10 people were killed and hundreds wounded during the 9 May protests, which authorities also said resulted in losses of 2.5 billion rupees ($9m; £7.2m).

The crackdown after was effective and harsh. Protesters who were jailed have spoken of abuse and despair.

"Sometimes the prison felt more like a graveyard. Like how we recite prayers at the graves of our loved ones, perhaps our families were reciting the same prayers when they came to meet us," said Abrar, who was released early this year after spending nine months in jail.

"My daughter would be crying and I could not wipe her tears,” he added.

Intizar, a fellow protester who was detained, told BBC Urdu prison officials "treated us as if we were terrorists, not Pakistanis".

"I told them I only protested and did not vandalise," he said.

He turned himself into police after they went after his family and broke the gate of his house in an attempt to locate him.

"I don't think we can ever describe what we and our families endured."

Former interior minister Rana Sanaullah said the events of 9 May 2023 were but a continuation of the PTI's protests in the past.

“The atmosphere had been created because the PTI founder was determined to prove itself more powerful than the state,” he said, referring to Imran Khan.

"How can anyone say that 'If I am arrested, it will be crossing a red line'? This is like a rebellion."

While a year has passed, political watchers say Pakistan will not be able to move on until the grievances of the protesters are addressed.

"I feel the state has only been venting its anger on this matter, as if trying to take revenge, instead of investigating it," said journalist Benazir Shah, who reported on the protests.

Ms Shah urged authorities to launch an investigation and make clear the roles of everyone involved.

"We will not be able to move forward until this is done. Until you answer the questions that have not been answered for the last one year, if the state remains silent, then we will not be able to move forward and we won’t be able to talk about the future,” she said.

But the military remains firm in its determination to punish those responsible for the protests.

"Negotiations cannot be held with an anarchist group," army spokesman Maj Gen Ahmed Sharif told journalists, while referring to the PTI.

“The only way forward is that such an anarchist group apologises to the nation and promises to leave the politics of hatred and participate in constructive politics.”

Protesters quoted for this story have been given pseudonyms for their safety.

Saad Sohail & Kelly Ng