Mrs. Arroyo cited the case of lawyer Rodolfo Paglinawan, who was shot dead on Thursday afternoon inside a food store in Cubao, Quezon City.
She said Paglinawan was allegedly the legal adviser of the labor union of a Marikina City-based food firm.
One of the assailants was apprehended by responding policemen and security guards of Araneta Center, Capitol Pawnshop and the barangay traffic aides of Quezon City.
"The arrested suspect was identified as Jeff Rafanan, an alleged member of the Rogelio Laurente command of the Partido Marxist-Leninist ng Pilipinas. Now I hope they will not blame again the military and police for this killing," Mrs. Arroyo said.
"When initially investigated, the suspect claimed that the victim was just collecting money for the labor union but nothing happened to the labor cases," she added.
Mrs. Arroyo is being criticized for creating a new commission, headed by retired Supreme Court justice Jose Melo, to investigate extrajudicial killings. Her critics say any efforts to investigate would be futile since the military and the police were behind the killings.
In her speech during the convention of the National Prosecutors League of the Philippines, Mrs. Arroyo urged them to be "squarely behind me in this fight against hideous elements challenging our political stability."
She also defended the Melo commission and said this would lead an investigating group to put political murderers behind bars and break the cycle of violence in the country.
"The work of the commission as far as pursuit of justice is concerned, will be investigative. It will also recommend administrative policies and legislation but the prosecution will be left to Chief State Prosecutor (Jovencito) Zuño and all of you wherever the crime may have happened," Mrs. Arroyo said. "And therefore the fight for justice will last beyond the life of the commission."
Zuño is one of the members of the commission, along with National Bureau of Investigation director Nestor Mantaring, University of the Philippines Board of Regents member Nelia Gonzalez and Butuan Bishop Juan de Dios Pueblos.
Mrs. Arroyo initially named Batanes Bishop Camilo Gregorio as member of the commission but he declined, saying he had to focus on his work in the Catholic Church.
She said the Melo commission would be given a sweeping mandate in carrying out its task, including enlisting the assistance of the various government agencies in the investigation of the killings.
Executive Secretary Eduardo Ermita said the body could also summon witnesses in the course of its investigation.
But critics of Mrs. Arroyo said the new commission was only meant to cover up the government’s failure to stop the bloodshed in the country.
They cast doubt on the commission’s credibility and its ability to fulfill its mandate, particularly with regard to reining in the military, which militant groups say is behind most of the killings.
Mrs. Arroyo has declared an all-out war against communist rebels. Ermita said the allegations being hurled against the military and the police could be part of the communists’ propaganda against the government.
"It is in my personal capacity as a citizen of the country and also my little experience regarding this matter that made me decide to accept the post," Pueblos said in an interview.
Pueblos stressed that his acceptance of the appointment was motivated by his "genuine concern" for the country, and was not intended to prop up the image of the President.
Earlier, Batanes Bishop Camilio Gregorio declined his appointment to the commission citing "more urgent pastoral obligations, and in deference to the CBCP (Catholic Bishops Conference of the Philippines)."
As with Gregorio’s appointment, Pueblos’ drew brickbats from the outspoken Lingayen-Dagupan Archbishop Oscar Cruz who described it as a proof of Mrs. Arroyo’s double-standard response to the role of the Church in political matters. He said accepting the appointment may even be a violation of Church laws prohibiting prelates from assuming civic powers.
"This administration is very touchy on bishops, priests who criticize its works. It would insist on the separation of the Church and State. But when you have bishops supporting President Arroyo, it would welcome such development and even appoint them to some commissions," Cruz, former CBCP president, said. — With Edu Punay