Several police teams are looking out for Khalid in connection with the sedition case registered over the controversial event at JNU campus last week, which led to the arrest of the varsity's students' union president Kanhaiya Kumar.
Syed Qasim Illyas Rasool in his complaint claimed that he received the phone call around 5 pm when he was in office.
"The caller identified himself as Mumbai-based gangster Ravi Pujari, threatened Rasool that he would kill his son Umar if he doesn't leave the country," police said quoting the complaint lodged by Rasool.
Umar's sister Maryam Fatimah told PTI that her younger sisters have received threats over the past few days on social media.
Umar's father also asked police to provide security to his family.