MANILA - Questions persist over the true role of the United States in the events leading up to the deadly encounter in Mamasapano and in the immediate aftermath.
Did the US provide all or part of the intelligence that formed the basis for the ill-fated Special Action Force operation?
Were its operatives involved in the planning of the mission and in its execution?
And why were personnel of the Federal Bureau of Investigation apparently ready to receive evidence after the clash went so horribly wrong?
In his first nationwide address after the Mamasapano incident, President Aquino said the government had received "actionable intelligence" around which the Mamasapano mission was built.
He said authorities had found not just the region, province or municipality but the very houses in which terror suspects Zulkifli bin Hir, alias Marwan, and Basit Usman were hiding.
In his statement at the Senate on Monday, relieved PNP-SAF commander Getulio Napenas Jr. said resigned PNP chief Alan Purisima told him last November to work with Police Supt. Fernando Mendez, director of the PNP Intelligence Group, on the use of the intelligence.
Napenas was told the PNP had an agent in the area and that the "intelligence packet" was subjected to long studies and served as the basis for the planning of the mission.
US Embassy Spokesman Kurt Hoyer has said the United States did not provide any intelligence to Philippine authorities in connection with the Mamasapano operation.
But several military sources have told The World Tonight Washington was in fact involved in the hunt for the two terrorists "from Day One."
The ABS-CBN News team learned from local residents that American soldiers were seen frequenting a private resort in Calarian, Zamboanga City a few days before the Maguindanao encounter,
The La Vista Del Mar resort in Calarian is located near the camp of the 84th Special Action Seaborne Company. It is believed the plan to attack Marwan's lair was hatched there last month.
But the resort's owner, Zamboanga City Rep. Celso Lobregat, said he has no idea if these reports are true.
The SAF camp has also remained closed since the Mamasapano incident.
What about reports that unidentified Americans took part in the actual operation?
In the days following the clash, remarks attributed to a spokesman of human rights group Suara Bangsamoro quoted a Mamasapano farmer as saying he saw the body of a Caucasian after the fighting.
But both the US Embassy and the Department of Foreign Affairs denied that any US soldier participated in the encounter.
"At the request of the Armed Forces of the Philippines, US service members serving in JSOTF-P (Joint Special Operations Task Force-Philippines) responded to assist in evacuation of dead and wounded after the firefight in Maguindanao," U.S. Embassy spokesman Kurt Hoyer said in a statement.
Hoyer said Americans only provided help in evacuating the dead and the wounded.
Several Americans were photographed in the area that day, dressed in civilian clothes and using civilian aircraft.
THE USE OF DRONES
What about speculation that the operation was monitored by drones?
Several media reports quote anonymous sources as saying there was an "eye in the sky" tracking developments on the ground in real time.
A member of the assault team, Senior Inspector Recaredo Marasigan, was even quoted as saying: "The source of the real-time intelligence was both technical and human."
At Tuesday's Senate hearing, Mamasapano Mayor Datu Benzar Ampatuan said he had seen some kind of white aircraft hovering over the town. But he could not confirm that it was, indeed, a drone.
"May lumilipad po na eroplanong puti. Hindi po natin masabi kung drone or kung ano. Paikot-ikot po," he said.
Napenas has told senators no request was made to the US for drones, and that the PNP has no such high-tech gadgets. Yet a military source has told The World Tonight, the non-lethal white phosphorus delivered by artillery in order to drive the attackers away can only be unleashed with the aid of a drone.
Adding another layer to the mystery surrounding the US role is the revelation that FBI agents were already in General Santos City two days after the clash, waiting for the turnover of physical evidence from Marwan's body.
Interior Secretary Mar Roxas told senators the sample did not pass through the PNP, and PNP officials could not provide a definitive answer as to how the sample ended up in the FBI's hands.
Police Director Benjamin Magalong, PNP Board of Inquiry chief, said he was told FBI personnel were standing by in General Santos City the Tuesday after the clash to receive the sample.
FBI spokesman Josh Campbell said the agency had no prior knowledge of the Mamasapano raid. But the circumstances beg the following questions:
Who coordinated the turnover of the sample, and on whose orders?
At what point was that coordination made?
How were FBI agents deployed so quickly?
Pressed by senators, Napenas said he would only provide answers in executive session.
With a number of key officials invoking executive privilege after being asked sensitive questions, it is anybody's guess whether the public will ever know all the answers.