Why are Palestinian police in the Sinai? (update)

From Ma'an:

A Palestinian police officer was shot and killed by Egyptian soldiers on Friday after he unwittingly drove his car into a military ambush, Palestinian police in the Sinai told Ma'an.

Imad Fayyad Abdallah, 38, was shot dead near the town of Sheikh Zuweid in the northern Sinai Peninsula.

He had driven his car into an area when Egyptian soldiers had set up an ambush targeting militant groups active in the area, and he failed to stop after warning shots were fired in the air, Palestinian police told Ma'an.

When he attempted to turn his car around to avoid the ambush, meanwhile, Egyptian soldiers opened fire, striking him in the head.

This brings up a number of points.

1. It goes without saying that no Palestinian Arabs will protest this killing even though anyone killed under similar circumstances by Israel would be the subject of numerous outraged protests, op-eds and UN speeches.

2. Egyptian media is, as far as I can tell, silent on this incident. In general, Egypt's media is under a gag order against reporting any civilians or innocents being killed in the protracted campaign against Islamists in the Sinai. However, sometimes, civilians are killed.

3. The story says that the source for this story was "Palestinian police" in the Sinai, besides the victim.

Al Moslim says that Abdallah was member of the Palestinian Authority and Fatah. Wattan TV said that he lived in El Arish, Egypt with his wife and three children, but that he was a colonel in the PA's Preventive Security Force.

Why are there Palestinian police in the Sinai?

UPDATE: It appears that Abdallah was one of many Fatah members, probably loyal to strongman Mohammed Dahlan, who fled Gaza when Hamas took over in 2007. (h/t Bob Knot)