They are listed as:
1. Ali Salim al-'Amari, head of security in Hadramawt
2. Ahmad Bawazir, head of political security in Sa'yyun
3. Salih Salim bin Bakawir, head of department of Criminal Investigation at al-Qatn.
4. Unnamed guard
5. Unnamed guard
The New York Times' Robert Worth has this brief on the ambush. Interestingly, Worth mentions former al-Qaeda commander, Hamza al-Qu'ayti, writing:
"Yemeni security forces have clashed with Al Qaeda militants several times in Hadramawt, the vast eastern province that borders Saudi Arabia to the north and the Arabian Sea to the south. In August 2008, Yemeni commandos killed Hamza al-Quayti, a top Qaeda commander, and four other militants. Al Qaeda has also assassinated local security officials in Marib, another eastern province where the government has little control."
Mareb Press also discussed the al-Qu'ayti and the August 2008 shootout that left five al-Qaeda suspects dead and 2 captured. I point this all out, as that attack followed the July 2008 suicide attack on a Sa'yyun military compound and two of the individuals killed in al-Qu'ayti's very localized cell were from al-Qatn, the same place as the assassinated chief criminal investigator.
As I mentioned yesterday this is not the first time - if al-Qaeda, and not someone else like drug dealers, is responsible - that al-Qaeda has assassinated security officials, including criminal investigators. For instance in 2007 it killed Ali Mahmud Qasaylah in an ambush.
News Yemen has pictures of the car after it crashed into a truck during the ambush.
Update: Some of the forums had this video as well.