National Bureau of Investigation (NBI) Regional Director Reynaldo Esmeralda said they have started taking statements from the "whistleblowers" in connection with the escape from the BI Bictutan Detention Center in Taguig.
Giving their statements were five overstaying foreigners, including an American, as well as two Chinese nationals arrested on drug charges.
Esmeralda said Department of Justice and NBI officials were conducting a surprise inspection of the BI facility when the seven detainees approached them.
During a check on the cubicles, inspectors confiscated 10 TV sets, 12 cellular phones, 20 bladed weapons and one satellite receiver.
The detainees then offered to provide information on the escape of Zhang, Sri Lankan Keerthi Jamayaha and Chinese nationals Tan Tin Shao and Go Sak Ping. Keerthi reportedly acted as a mediator between the BI officials and detainees seeking special favors.
"They would provide us with the information on how the detainees escaped and the involvement of the jail guards," Esmeralda said. "In return for their cooperation, the detainees hope to get back privileges like their TV sets and cell phones, which they said served as the only means of communication with their families."
The NBI official said that while these privileges are against prison rules, the DOJ might be swayed into granting them their wish in exchange for information.