Citizenship Amendment Bill
The gunman reportedly shouted "Delhi Police zindabad" and "yeh lo azaadi".
The incident occurred days after Union minister Anurag Thakur and other BJP leaders made communal remarks and speeches.
The UP Police has accused Khan of sowing seeds of discord and disharmony towards other religious communities among the students.
The human chain was formed as a protest against CAA.
The Uttar Pradesh government's move raises several questions because the centre has not yet notified the rules for the implementation of the CAA.
Shrikant Sharma, Uttar Pradesh energy minister and govt spokesperson, said in an interview that activists who alleged brutality by the police should move court or complain to the SITs.
Sadaf Jafar was the only woman arrested by the UP Police after the anti-CAA protests in Lucknow on 19 December.
The family of Sadaf Jafar, the only woman arrested by the UP Police after the anti-CAA protests in Lucknow, allege she has been beaten in custody.
On Wednesday, Vijayan had rejected criticism of the resolution, saying the state assemblies had their own privileges.
Thousands of people participated in the rally against CAA organised by Muslim organisations.