Lawyer Efren Meneses Jr., chief of the NBI Anti-Fraud and Computer Crimes Division, told reporters three of the witnesses are former suspects, while the other four are among the survivors of the bombing.
"I have prepared a letter of request (to the justice department) for the witnesses to be included under the (Witness) Protection Program," he said.
However, Meneses refused to reveal the names of the seven witnesses for "security reasons."
Meneses said investigators have not found any evidence to link Sen. Panfilo Lacson and the defunct Presidential Anti-Organized Crime Task Force to the bombings, which killed 22 people and left many others wounded.
But Meneses hinted that the Rizal Day bombings could be connected with the attempt of one Elmer Jamia to smuggle a bomb into Malacañang on Nov. 30, 2000.
Meneses said the three suspects-turned-witnesses told investigators they had been paid to join anti-government rallies to protest the all-out war that then President Joseph Estrada had launched against the Moro Islamic Liberation Front (MILF).
At the height of the military offensive, the MILF leadership had threatened to "take the war" to Metro Manila to stop Estrada from ordering the capture of their camps.
Investigators said the bombers were led by Hadji Onos, an explosives and demolition expert and former member of the MILF and Moro National Liberation Front (MNLF), and Sammy Arinday, who ordered Onos to recruit the bombers in Lanao del Sur and other parts of Mindanao.
The other alleged bombers were: Col. Efren Torres, Amir Dimaampo, Salvin Camama, Ibrahim Guindolongan, Roberto Onyot, and Rogelio Cagadas.
Police linked Camama, a former MNLF member, and Guindolongan, former MILF member, to the car bomb that blew up on the parking lot of the Ninoy Aquino International Airport centennial air cargo on Dec. 30, 2000.
Torres was said to have acted as go-between for Onos and Arinday, while Dimaampo had accompanied Arinday in his tour of Metro Manila.
Onyot reportedly met in Antipolo City with Jamia, who was caught by presidential guards trying to sneak a bomb into Malacañang during the Estrada administration.