Long was probably finding justification for gratuitous violence, and there is plenty of that in Islamic holy texts.
“La. cop-killer left suicide note, Islamic verse, trail of rage,” Boston Herald, July 1, 2017 (thanks to The Religion of Peace):
The military veteran who killed three law enforcement officers in Baton Rouge last summer left behind a suicide note, a prayer from an Islamic holy book and an online trail of his rage against police.
Two days after a white police officer shot and killed a black man in Louisiana’s capital, Gavin Long searched the internet for addresses, phone numbers and other personal information belonging to the two officers involved in the July 5 shooting of Alton Sterling, a prosecutor’s report revealed Friday.
Less than two weeks later, the 29-year-old black man from Kansas City, Mo., traveled to Baton Rouge and ambushed law enforcement officers outside a convenience store and car wash near police headquarters.
Armed with a semi-automatic rifle that he legally purchased, Long fatally shot three officers and wounded three others on July 17 before tactical officers killed him, ending a gun battle that lasted nearly 14 minutes that Sunday morning….
He also left a printout in his car from an Islamic holy book that was mostly in Arabic