I disagree. Did you consider a person who is normally used to writing from right to left (as in Arabic). By the way, I am left-handed.
I'm left-handed too. I also sm an engineer, who was taught to block letter write in all of my reports. My cursive writing is horrible (thank God for computers) so block lettering is my normal writing style.
The inconsistencies in the lettering os what makes this person's writing unique.
I'm sure the FBI analysts are coming up with even better profiles, but it doesn't hurt to brain storm on FR. Who knows we might actually stumble on something of value that the FBI could use to catch this terrorist.