Trooper Mozo is located in the Field of Bone at the East Cabilis Entrance, on the right hand side. His /loc is -2559.01, 3566.18, 7.85. If you are kill-on-site when using illusion Iksar (potion or chanter cast) then you need to go kill until you are dubious with the Legion of Cabilis (warrior guild all the troopers are on).
My suggestion is to kill the Iksar Bandits in Warsliks Woods as they give + Legion of Cabilis Hits as well as + Brood of Kotiz hits (necro guild, and only way to get them that is practical). You can also kill the goblins in Warsliks for faction hits for Legion of Cabilis. There are other options, but some of them impact other factions some players would wish to keep intact.
Once you con dubious be prepared to hand in many stacks of bone chips. My Drakkin necro handed in approximately 3k + bone chips before maxing out at dubious without illusions. Other races/deities would have a greater maximum faction (Drakkin and Veeshan are very low on the faction tree). This makes sense as 4x bone chips = 1 faction hit, so a stack of 100 chips is only 25 faction ups.
If you are standing between mozo and the burning torch you do not seem to garner aggro from the pathing-by crusaders. This was my experience, however I maintained my illusion so most of the time I was no lower than threatingly.