Dahlan o Dahlan: a slip by Shin Bet in NYT

"Indeed, Hamas has shown only hostility to anyone perceived as cooperating with Israel. Yuval Diskin, chief of Israel’s Shin Bet internal security agency, told the cabinet here on Sunday that Hamas had cold-bloodedly killed about 70 Fatah supporters in Gaza under the cover of the war." This is quite a revelation. Why is the Shin Bet chief reporting about "Fatah supporters" if they were not working for...Shin Bet? This paragraph is quite funny.