MANILA, Feb. 5 (Xinhua) -- Philippine Interior and Local Government Secretary Eduardo Ano said on Tuesday that Indonesia has expressed willingness to help Philippine authorities identify the Indonesian "suicide bombers" that carried out the twin blasts on Jan. 27 which left 23 people dead and more than 100 others wounded.
"It is officially confirmed that (the Jolo incident) was a case of suicide bombing. The bombers for both explosions are Indonesian couple," Ano said.
The conclusion is based on post blast and forensic investigation as well as the testimonies of survivors, Ano said.
He said authorities are in the process of identifying the Indonesian bombers. "It may take time. The Indonesian government is willing to assist," he added.
On last Monday, the Philippine National Police (PNP) filed multiple murder and frustrated murder charges against alleged members of the Abu Sayyaf Group suspected of plotting the Jolo blasts.
PNP Chief Director General Oscar Albayalde said the five suspects led by Kamah Pae have surrendered to police over the last weekend.
The PNP also filed charges against 14 other suspects still at large, including the group's leader Hatib Hajan Sawadjaan, alias "Imam".
All suspects are facing 23 counts of murder, 95 counts of frustrated murder, and a case of damage to property, according to Albayalde.
Albayalde said that the suspects were part of a 22-member Abu Sayyaf band led by Hatib Hajan Sawadjaan.
Three other suspects, including two suicide bombers believed to be Indonesian male and females, have died.