(CNN) -- Philippines police say that at least two people who were at the scene of last month's massacre in the country's south have implicated a mayor as being involved in the killings, state media reported Thursday.
The two are among 161 suspects in the November 23 killings in Maguindanao province. Fifty-seven people, including 30 journalists, died in the attack.
Some of the suspects are in custody, others are being sought, the Philippines News Agency said.
Immediately after the killing, suspicion fell on Andal Ampatuan Jr., the mayor of Datu Unsay municipality and the son of the powerful governor of Maguindanao. Authorities have recommended that Ampatuan be charged with 25 counts of murder.
"We have two (witnesses). Because they were in the crime scene, these two have direct testimony linking the mayor to the crime," the country's National Police Director Raul Castaneda was quoted as saying by the news agency.
Also Thursday, the Congress met for a second day in a joint session as lawmakers questioned President Gloria Macapagal Arroyo's Cabinet members about a martial law that was imposed on the province Friday.
The martial law allows arrests without a warrant. The army has said it is necessary to impose peace following what has been called a politically motivated massacre. Critics contend that it sets a dangerous precedent.
Violence in the run-up to elections is not uncommon in the country. The Maguindanao massacre, however, is the worst politically motivated violence in recent Philippine history, according to state media.
The victims included the wife and sister of political candidate Ismael "Toto" Mangudadatu, who had sent the women to file paperwork allowing him to run for governor of Maguindanao.
He said he had received threats from allies of Gov. Andal Ampatuan Sr., the father of the accused mayor, saying he would be kidnapped if he filed the papers himself.
Maguindanao is part of an autonomous region in predominantly Muslim Mindanao, which was set up in the 1990s to quell armed uprisings by people seeking an independent Muslim homeland in the predominantly Christian Asian nation.