As Allah notes, this is a classic trigger for workplace murders, having nothing to do with religion.
When I say "the process of being terminated," I mean that in specific present tense: He was actually being fired in the very minutes before his rampage.
That doesn't mean religion doesn't have anything to do with this -- Why was he being fired? Was it due to his attempts to convert co-workers while on the job?
And his choice of manner of murder is suggestive.
However, it should be said that the motive here is not clear. I suspect a mixture of motives -- sudden distress plus certain thoughts already lurking around his brain -- but we don't know that yet.
Signature: Why behead the woman?
Beheading, I imagine, is a fairly long process, requiring a lot of muscular effort.
It is harder and takes longer than stabbing.
Interesting read, especially this paragraph...
Different methods -- the Algerian beheading was a group effort, and was coordinated, whereas the American beheading seems to have been what the FBI would call a "disorganized" type of attack, and seemingly impromptu -- but nevertheless, one Frenchman and one American woman beheaded, just as IS asked.