Shadab was arrested on Friday, and is still in jail.
Speaking to reporters here, Lallu said, "Congress will always stand behind the victims of police harassment. Police is picking up innocent people and even arresting them under serious sections and harassing people."
He added that the Congress will continue its protests to save the Constitution as the new citizenship law is totally unconstitutional.
Lallu also met imam of Jama Masjid Maulana Abdul Jalil Mazahiri. PTI CORR NAV IJT