It began with a walk-in. In August 2010 a former senior Pakistani intelligence officer approached Jonathan Bank, then the CIA's station chief at the US embassy in Islamabad. He offered to tell the CIA where to find bin Laden in return for the reward that Washington had offered in 2001. Walk-ins are assumed by the CIA to be unreliable, and the response from the agency's headquarters was to fly in a polygraph team. The walk-in passed the test. The US initially kept what it knew from the Pakistanis. The fear was that if the existence of the source was made known, the Pakistanis themselves would move bin Laden to another location. So only a very small number of people were read into the source and his story. The CIA's first goal was to check out the quality of the informant's information. The compound was put under satellite surveillance. The CIA rented a house in Abbottabad to use as a forward observation base and staffed it with Pakistani employees and foreign nationals. Later on, the base would serve as a contact point with the ISI; it attracted little attention because Abbottabad is a holiday spot full of houses rented on short leases. A psychological profile of the informant was prepared. The informant and his family were smuggled out of Pakistan and relocated in the Washington area. He is now a consultant for the CIA.