They admitted to doing the crime out of hate for Jews. As revenge for "how the Jews hurt the Arabs" in the Arab riot against Jews that happened last Yom Kipur.
The article is in Hebrew, auto translated: here.
I abhor these racist riots and condemn both sides. I put the blame on the 2000 Arab on Jews riots which coincided with the "2nd Intifada". Out of the blue, with no reason, Arabs all over Israel - including Akko - thought it was prime time to violently attack Jews. At that point, a certain calm and peaceful co-existence was shaken and destroyed for generations.
Hate and distrust will linger for many years to come.