Philippine forensic experts look for evidences insidethe tourist bus in Manila.
Philippine police said on Monday they may punish officers who posted Facebook photos of themselves posing and smiling beside a hijacked bus where Hong Kong tourists were shot dead during a hostage crisis.
The pictures, which were taken after the hijacking and before the bullet-riddled bus
was removed from the street, were circulated on the social networking site as well as other online forums.
The emergence of the pictures has stoked anger over the handling of the crisis, in which eight hostages and the gunman died, and the perceived insensitivity of Philippine authorities in the aftermath of the tragedy.
"They are being asked to explain why they did that act," metropolitan Manila district police chief Director Leocadio Santiago told ANC television.
"Was it conducted with malice, what was their intention?"
He said those in the photos clearly violated a police rule on proper decorum, and could be demoted pending results of an investigation.
Santiago said three of the police officers had already been identified, while four others were still being sought.
"The Facebook photos are a public document. We can use that for and against them, they can be held accountable for that," Santiago said.
A sacked police officer hijacked a busload of Hong Kong tourists in the heart of Manila last Monday, in a bid to be cleared of extortion charges and get his job back.
The 12-hour standoff ended in a botched assault by police with the events aired live around the world on television.
The crisis triggered public anger in Hong Kong and mainland China, with many questioning the competence of the police amid their own admissions of blunders.
Aside from the perceived bungling of the situation, tensions have been inflamed by the response of Philippine authorities in the days after the hijacking.
President Benigno Aquino apologised to people in Hong Kong after he was seen smiling at a press conference called shortly after the ordeal ended.
The Chinese embassy in Manila also released a statement on Friday expressing outrage after television footage showed a Philippine national flag draped in honour over the gunman's coffin a day before his funeral.
Following the statement, the Philippine government quickly acted to have the flag removed.