CALAMBA CITY -- Police have provided tight security for the lone witness to Friday's grisly bank robbery in Cabuyao, Laguna, where nine people were shot dead execution-style by the robbers, police said Saturday.

Police personnel were sent to guard the hospital where Isagani Pastor, who survived the killing spree, was being treated, said Senior Supt. Felipe Rojas Jr., Laguna police director.

Pastor, Rizal Commercial Banking Corporation's (RCBC) marketing manager, was at the Intensive Care Unit and remained in critical condition. His doctor has not allowed the police to speak with him.

"(Pastor) has to recover because he is the only witness to the crime," Rojas said.

Pastor's room number was not disclosed to anyone except his relatives, he added.

Police are holding two security guards of RCBC, who could not be found immediately after the robbery and killings were discovered Friday morning, and were investigating them for possibly being linked to the robbery.

Rojas said investigators found inconsistencies in the statement of one of the guards but gave no details.

On Saturday morning, police officials conducted a case conference to discuss the respective assignments of the various police units involved in the investigation. These include the Criminal Investigation and Detection Group, National Bureau of Investigation, Laguna Police and Regional Special Operations Group.