The Jerusalem Post's Khaled Abu Toameh led with what should be the most important parts of this story, especially to US readers (emphasis mine throughout):
Palestinian Authority security officials accused supporters of al-Qaida in the Gaza Strip of carrying out Sunday's attack on a UNRWA-run school [U.N. Relief and Works Agency] in Rafah in which one person was killed and six others were wounded.
"There is no doubt that al-Qaida is operating in the Gaza Strip," a senior PA security official said. "Today's attack carries the fingerprints of al-Qaida." (...)
Local residents and PA security officials said the attackers belonged to a new al-Qaida group identified with Salafism [Wahhabism] - a school of thought that takes the pious ancestors [Salaf] of the patristic period of early Islam as exemplary models.
The Jerusalem Post also included this statement by Fatah legislator Majed Abu Shamalah, a speaker at the celebration whose bodyguard was killed in the attack:
"The celebration did not violate Islamic law," he said. "These mercenaries do not represent the real Islam. I call on all Palestinians to stand against this bunch of ignoramuses who are leading the Palestinians toward the abyss."
They also differed in explanations. The Jerusalem Post explained that PA senior officials and eyewitnesses said “at least 70 Muslim fundamentalists” at the school where both UNRWA and PA officials were present and “began chanting slogans denouncing the event as immoral” because they claimed “girls and boys were asked to dance together in violation of Islamic teachings.”
While all three articles mentioned recent violence, only the Jerusalem Post linked it to Al Qaeda and explained the group's sharia crackdown:
The Salafis and other al-Qaida-linked groups, including the Righteous Swords of Islam, are believed to be behind a series of attacks on young women, Internet cafes, hair salons, restaurants, schools and foreigners in the Gaza Strip over the past two years.
The AP's Barzak ignored the reason for the violence and left out the ties to terrorism:
While the sides have largely halted their attacks on each other, Gaza continues to be plagued by clan violence, kidnappings and other crime. The violence has included a string of attacks on Internet cafes, music stores and restaurants by Islamic extremists.
After all of that, Barzak still couldn't explain the motive for the attack:
It was not clear why the extremists objected to the event at the school in the town of Rafah, or whether they were behind the shooting, the officials said. The gunmen were masked, making identification difficult, security officials said.
It isn't clear? In the past year, Palestinian leader Mahmoud Abbas stated that Al Qaeda has spread to the West Bank and Gaza Strip and is active--a story the traditional US media largely ignores. In that spirit, the AP, one of the two main wire organizations which provide the source for much of the US media's news, did not include this troubling information about the PA linking the attack to Al Qaeda and targeting Palestinian political leaders. The news is there, the media just aren't reporting it.