from the article:
The man arrested, Sheikh Mohammed Rehan, allegedly drove with Shahzad from Karachi to Peshawar on July 7 in a pickup truck, authorities said. They returned to Karachi July 22. It is not known why they went to Peshawar or with whom, if anyone, they met there.
Peshawar is a large, mostly Pashtun city perched on the edge of Pakistan’s tribal areas, where Al Qaeda, the Taliban and other militant groups maintain strongholds. It is also where Shahzad’s father and other relatives live.