- Anshu Prakash says he was attacked in the presence of Arvind Kejriwal
- He said he was "held in the collar" by lawmaker Amanatullah Khan
- AAP has called the allegations "ludicrous"
Here are the 10 latest developments in this big story:
Late evening, the police, which has registered cross-cases filed by the AAP lawmakers and the top bureaucrat, later detained AAP lawmaker Prakash Jarwal for questioning about the alleged assault.
In his complaint, Anshu Prakash says "the assault was premeditated and in conspiracy of all present... None of the persons present in the room made any effort to save me." Home Minister Rajnath Singh has asked for a report. According to the chief secretary, he was summoned to Mr Kejriwal's home at midnight to discuss delays in the release of TV ads on three years of AAP. The Chief Minister's office, he says, called repeatedly to make sure he would comply.
Besides Mr Kejriwal and his deputy Manish Sisodia, there were around 11 MLAs when he arrived for the meeting, he said, and one of the MLAs "firmly shut the door".
The chief secretary says he was seated between two MLAs and asked by Mr Kejriwal to explain the delay in releasing a three-year anniversary TV campaign. Soon, the MLAs shouted at him and threatened him, he alleged. "One MLA, whom I can identify, threatened that I will be confined in the room for the entire night unless I agree to release the TV campaign," he said.
Amanatullah Khan and Prakash Jarwal, who flanked the bureaucrat, "started hitting and assaulting me and hit several blows with fists on my head and temple," alleges Mr Prakash, who drove straight to Lieutenant Governor Anil Baijal's house to complain.
The IAS (Indian Administrative Service) officers' association has demanded the arrest of the AAP lawmakers. In the evening, the Delhi IAS association said bureaucrats will boycott all meetings called by ministers till the chief minister apologises. Some 200 IAS officers also held a candlelight march from Raj Ghat to the Delhi Secretariat on Tuesday evening.
AAP calls the allegations "ludicrous"; it says the chief secretary had been called at 10 pm but he came two hours late for discussions on a subject that was "deeply worrying" for MLAs - the faulty implementation of Aadhaar that left lakhs without food. The ruling party denied that its meeting was on ads.
"He even used bad language against some MLAs and left without answering any questions," said AAP in tweets. A leader said the CCTV footage proves that Mr Prakash was "perfectly fine" when he left the residence and was "even followed by an MLA who tried to talk to him".
Ties between AAP and Delhi bureaucrats have been strained since the party came to power in 2015 because of an incessant power tussle. The Delhi government has no control over important departments like law and order, land and police. AAP accuses the Lieutenant Governor and bureaucrats of obstructing it at every turn on the orders of the BJP-led central government.
The timing of the controversy couldn't have been worse for Mr Kejriwal's party, which is fighting the disqualification of 20 lawmakers for holding "offices of profit". If it loses in court, by-elections will be held for those seats.