Jain had previously said he had not seen anything as he had gone to the washroom at the time of the incident on Monday night.
"New facts have emerged in the case. The advisor to the CM is being interrogated and his statement under Section 164 of the CrPC has been recorded. He has given us four names. The police custody of both the MLAs is required to unearth the whole conspiracy," the prosecutor said moving a fresh plea for their custody.
Khan and Jarwal were today sent to a 14-day judicial custody in Tihar Jail by the court, which reserved its order on their bail pleas for tomorrow.
During the hearing today, Shrivastava told the court that Jain had called the chief secretary for a meeting at 08:45pm on Monday, and at 10:00pm the officer confirmed to him that he would attend the meeting.
Advocate Rajiv Mohan, appearing for Prakash, also supported the plea for police custody, saying the alleged attack on the officer was pre-meditated and was witnessed by the CM's adviser.
In his statement, Jain said when the meeting started, Kejriwal said that MLAs wanted to discuss certain issues but randomly all of them started questioning the chief secretary about the delay in the release of funds for AAP government's media publicity on its achievement in education and fighting corruption.
Jain was picked up by the Delhi Police yesterday morning from his residence at Maharani Bagh in connection with the case.
The chief secretary has alleged in his complaint that he was sitting on a sofa flanked by Khan and another AAP MLA during the meeting.
"Khan and the other MLA, without provocation from my side started hitting and assaulting me with blows on my head and temple," he alleged in his complaint.