Marcos blamed the
communists and subsequently suspended the privilege of the
writ of habeas corpus. During the police investigation into the bombing, Manila Mayor
Antonio Villegas was initially named the primary suspect of the bombing, but later evidence suggested otherwise. Suspicion of responsibility for the blast fell upon incumbent President
Ferdinand Marcos. At the time, there was suspicion that Marcos perpetrated the bombing as a pretext for his declaration of martial law. There were a series of deadly bombings in 1971, and the CIA privately stated that Marcos was responsible for at least one of them. The agency was also almost certain that none of the bombings were perpetrated by Communists. Defectors from Marcos' cabinet also contained further evidence implicating Marcos. A proven
false flag attack took place with the attempted assassination of Defense Minister
Juan Ponce Enrile in 1972. President
Richard Nixon then approved Marcos' martial law move on the rationale that the country was being terrorized by Communists. Some prominent personalities laid the blame on the
Communist Party of the Philippines (CPP) under
Jose Maria Sison.
Jovito Salonga, in his autobiography, stated his belief that Sison and the CPP were responsible. Retired
Armed Forces general
Victor Corpus, a former
New People's Army member who defected from the group in 1976, alleged in a 2004 interview that Sison dispatched the cadre who attacked the meeting with a hand grenade. In the prologue of his 1989 autobiography, Corpus claimed that he was present when some leaders of the CPP discussed the bombing after it took place. In interviews by
The Washington Post, unnamed former CPP officials alleged that "the (Communist) party leadership planned -- and three operatives carried out -- the attack in an attempt to provoke government repression and push the country to the brink of revolution... Sison had calculated that Marcos could be provoked into cracking down on his opponents, thereby driving thousands of political activists into the underground, the former party officials said. Recruits were urgently needed, they said, to make use of a large influx of weapons and financial aid that China had already agreed to provide." José María Sison has denied these accusations and the CPP has never claimed responsibility for the incident. Historian Joseph Scalice has argued that "the evidence of history now overwhelmingly suggests that the Communist Party of the Philippines, despite being allied with the Liberal Party, was responsible for this bombing, seeing it as a means of facilitating repression which they argued would hasten revolution." Sison, however, continued to deny this claim, arguing that Scalice, alongside his primary source, columnist
Gregg Jones used sources from military intelligence and rejectionists. ==Aftermath==