The order of the city government to tear down the Hiya Unsanna Mosque is believed to have triggered the March 3 killing of Mayor Luis Biel II.
A young assassin gunned down Biel, but he himself was shot dead by the mayors security aides.
Biel was buried yesterday in the familys private mausoleum with thousands of followers and sympathizers, all clad in red shirts, joining the funeral procession.
Biels remains were paraded around the city with majority of business establishments temporarily shutting down to join the call for justice for the slain mayor.
Mrs. Arroyo sent Dureza, presidential adviser on the peace process, here last Friday to extend her condolences to Biels family and separately meet with city officials and the leaders of the Hiya Unsanna Mosque.
Dureza appealed to both parties to resolve the looming crisis peacefully, vowing to help find a "win-win solution" to the problem.
Accompanying Dureza in the dialogues were Basilan Bishop Martin Jumuad and Vice Gov. Alrashid Sakalahul.
Dureza expressed apprehension that if the tension is not defused, a third party such as the extremist Abu Sayyaf might take advantage of the situation by launching terrorist attacks.
"Let us not squander the gains Basilan has been experiencing," Dureza said, citing the stable peace and order situation in the province, which used to be a haven of the al-Qaeda-linked Abu Sayyaf.
Dureza relayed Mrs. Arroyos desire for both parties to heed to an initial move to defuse the tension: hold the demolition order in abeyance, and build a new mosque in the vicinity to prevent the Muslim worshippers from being dislocated.
"Let us calm the situation first. This is not a conflict between Muslims and Christians," Sakalahul said.
The Muslim religious leaders have vehemently denied that Biels assassin, Javer Gani, a college student, was one of their worshippers, saying he was "a stranger to us."
Authorities expressed apprehension that Ganis suicide attack might become a precedent.
Gani was alleged to have been seen making his last bow and ritual at the mosque, tying knots on his vital parts, before he committed the sabil (suicide attack).
Sakalahul, however, believes that Gani committed the suicide attack out of sheer frustration in life and driven by his extreme belief that he would die defending his faith.
"I think it was the first suicide attack but I believe that it was purely personal, that no groups were involved as the suspect was reportedly suffering from depression because of too much problems and driven by extreme faith," he said.
Sakalahul said Ganis brother, who reportedly joined the Abu Sayyaf, had been killed, and that their parents are both deceased.
Fearing that the suicide attack might become a precedent, Sakalahul called on Muslim religious leaders and imams (priests) to guide their followers away from extremism.
"There is a Muslim belief that if you die fighting for your faith, you will go straight to heaven," he said.
Dureza, who inspected the place where Biel was gunned down, said it was very much enclosed, with little leeway for Gani to escape, forcing him to instead opt for a suicide attack.