Relatives of the detained men said they were being targeted for being devout Muslims.
"Saying prayer is his crime, fasting is his crime, being Muslim is his crime," he Dawn quoted Saima Shahid, wife of Shahid Hussain, who is said to have arranged financial help for Shahzad's terror plot.
Afzal Inayat, uncle of another suspect, Ahmed Raza also maintained that his nephew was being targeted for his religious beliefs.
"He (Raza) sports a beard. He is religious in the sense that he says his prayers and fasts.That doesn't mean that he is an extremist," said Inayat.
Raza, who has an MBA degree, worked at an upscale catering company co-owned by one Salman Ashraf, who is the third suspect arrested by Pakistani security forces in connection with the May 1 botched terror plot.
"He is a normal, business-minded person," said Rana Ashraf Khan, Raza's father.
Pakistani intelligence agencies have arrested several persons, including an Army Major since the failed bombing plot for aiding and assisting Shehzad.
US officials had earlier said that they have growing evidence that a Pakistani Army Major had been in telephonic contact with Shahzad.
US officials said they were aware of cellphone traffic between Shahzad and the unidentified Pakistani military officer.
Sources said the major had cellphone contact with Shahzad on May 1, including a conversation that occurred as the Pakistani American was allegedly parking his SUV rigged with propane tanks, fertilizer and fireworks at the busy Times Sqaure.
US officials said they could not confirm that timing of the conversations between Shahzad and the military official.