Prakash Kumar, 35, was arrested from Hub on Wednesday after locals complained he allegedly sent blasphemous content via WhatsApp, police was quoted as saying by local media.
Police said they had lodged a case against the accused while a cellphone, from which the suspect allegedly shared blasphemous content, has been seized. A local court has sent the suspect to jail for further interrogation in the case.
A mob soon gathered outside the Hub city police station demanding that Kumar be handed over to them so they could "punish" him. When law enforcement refused, the crowd turned violent.
The police managed to disperse the crowd using tear gas shelling and aerial firing, and also took scores of protesters into custody.
According to police, a teenager died in the violence. The boy was a resident of Pathan Colony and became a victim of aerial firing during the clash which took place near Gaddani bus stop in Hub.
Blasphemy, which carries the death penalty, is a sensitive issue in Pakistan, with allegations often prompting mob violence.
Vigilantes have murdered 65 people over blasphemy allegations since 1990, according to research compiled by the Centre for Research and Security Studies think-tank.