© Sohail Shahzad/EPA-EFEPakistan Tehreek-e-Insaf's supporters gather in Rawalpindi on Sunday to protest Imran Khan's removal from government
While he has not responded to the charges himself, his lawyers appealed for pre-arrest bail on Monday at the Islamabad High Court, which granted Khan protective bail until Thursday, when he is likely to appear before an anti-terrorism court in the capital.
Why was Imran Khan charged?
In a speech on Saturday evening in Islamabad to protest the arrest and alleged torture of his close aide Shahbaz Gill, Khan was accused of "threatening" state officials and promising to mount a legal challenge after Gill was arrested on August 9.
Khan singled out senior Islamabad police officials and a female judge who earlier in the week approved detaining Gill for two days. Gill faces sedition charges after he was accused of inciting mutiny against the country's powerful military.
He accused police of torturing Gill in custody and said the charges against his ally were part of "a conspiracy" to pit his party against the military. Police have denied the torture allegations.
"When I asked Islamabad police 'tell me what did you do [to Gill]', I was told that 'we did nothing. We got a boot from behind [to follow orders]'," Khan said in his address.
Islamabad police denounced Khan's comments and warned anybody "threatening the police or making false accusations will be dealt with according to the law".
Pakistan's media regulatory authority in a statement on Sunday accused Khan of levelling "baseless allegations" and "spreading hate speech" against "state institutions and officers", and placed a ban on live broadcasts of his speeches on national television.
Pakistan's Interior Minister Rana Sanaullah also delivered a news conference on Sunday in which he said the government is exploring options to file a case against the former prime minister for his "provocative speech".
Comment: So the government is using anti-terrorism laws against Khan because he accused them of torturing his aide and for his calling out the corruption.
The slow buildup in the standoff reached a crescendo on Sunday night when a formal police report was filed against Khan.
Why was anti-terrorism law invoked?
The police report against Khan includes testimony from Magistrate Judge Ali Javed, who described being at the Islamabad rally on Saturday and hearing Khan criticise the inspector general of Pakistan's police and another judge.
"You also get ready for it, we will also take action against you. All of you must be ashamed," Khan reportedly said.
Khan could face years in prison with the new charges, which accuse him of threatening police officers and the judge under the country's sedition act, which has its roots in a British colonial-era law.
The Anti-Terrorism Act itself was conceived in 1997, and there are various clauses and caveats, with the harshest penalties being capital punishment and a life sentence in prison.
However, the lesser charges levied against Khan during his recent campaigning against the government do not relate to the act.
What led to this moment?
Ever since his government was toppled in April, Khan - the chairman of the Pakistan Tehreek-e-Insaf (PTI) - has carried out a huge public outreach effort, during which he delivered blistering remarks against his political opponents, state institutions, police and, in particular, "neutrals", a commonly used euphemism for Pakistan's military establishment.
Khan has alleged he was removed from power as part of a "foreign conspiracy", pointing the finger of blame at the United States, though he has not provided any proof for the accusation.
But he has reserved his choicest remarks about the military establishment, which he has been exhorting to 'not remain neutral' and not side with the ruling coalition, which Khan has labelled as "corrupt" and "thieves".
In the latest speech in Rawalpindi on Sunday night, he addressed thousands of people as he continued to rail against the "neutrals" while blaming them for cracking down on his party workers in May, when he announced a long march to Islamabad.
"On May 25, when police perpetrated violence against us, I was told by insiders that police acted under orders by above, which means they were under pressure by the neutrals to thrash PTI workers," he said, adding "are the neutrals really neutral?"
He questioned the neutrality of the Election Commission Pakistan (ECP) for making "every decision against PTI" and alleged the head of the ECP was also under political pressure.
What is quite ironic in this current turmoil, which has captivated the republic of 220 million people, is that many political observers have suggested the military was the architect of Khan's initial political success, although both sides have publicly denied this.
Will Khan be jailed?
Under Pakistan's legal system, police file what is known as a First Information Report (FIR) detailing charges against an accused person to a magistrate judge, who gives the green light for the investigation to go ahead. Police then arrest and question the accused.
Khan's lawyer Faisal Fareed Chaudhry said he believes the FIR will be immediately quashed as it is in clear violation of a previous Supreme Court verdict.
Other legal experts Al Jazeera spoke to agreed the report was not legislatively watertight and it would be dismissed. Constitutional expert Abuzar Salman Niazi said the FIR against Khan has no merit.
"It is perfect case of quashment before the high court. Terrorism under the Anti-Terrorism Act 1997 has a very restricted application in limited circumstances. Simply saying 'we will take action against you' does not amount to terrorism. It does not even amount to criminal intimidation under the Pakistan penal code," Niazi said.
Comment: And yet these attempts to unjustifiably jail Khan reveal just how corrupt the Western-allied establishment in Pakistan is, and how threatened they feel by him, which also adds further credence to his claims that the coup was a conspiracy to remove him from power, which was, in part, because of his plans to have constructive relations with Russia; as evidenced by the food and fuel deals he set up whilst in office.
Procedurally, Khan needs to confirm protective bail from the lower court on Thursday. Once the confirmation is given, he cannot be thrown into jail.
"However, if that does not happen, in that case he could be taken to the jail. But we must keep in mind that anti-terrorism cases in Pakistan are usually not on merit and it is used as a political tool," added Niazi.
Terrorism law and 'political persecution'
In a statement to Al Jazeera, John Sifton, Human Rights Watch's Asia advocacy director, said Pakistan's terrorism law is overly broad, "contains vague language", and has been used in the past to "curtail political speech".
"If the authorities feel that Khan's remarks constitute incitement to violence or constituted a real threat to public officials, there are other laws which can be used to prosecute him," said Sifton.
Asad Rahim Khan, a Lahore-based lawyer and legal analyst, agreed there is no merit to the charges but added Khan was "deeply irresponsible" in making his statement on Saturday.
"He called for legal action against state officials that he thought were acting against him and his party, and his tone was belligerent. To equate this with terrorism, however, is no more than a ham-fisted attempt at political persecution."
What happens next?
The former prime minister must appear before the anti-terrorism court on Thursday, according to criminal law expert Haider Rasul.
"Imran Khan has to be there in person. The case cannot be dismissed on merit alone. He has to appear before court, submit his bail bond, and it is quite likely he will be given an additional bail of few more days," he said.
Rasul said that Khan could be formally arrested in the unlikely event the court rejects giving Khan bail - but this was highly unlikely.
Politically, however, any such step could result in fanning the flames further. A large number of people have shown their displeasure at the removal of Khan's government and this would only heighten the uncertainty and instability that has left Pakistan in a precarious situation economically.
Hit them out of the stadium for a sweet 10