Magick is but energy this is true, but if you influence someone to do something is that not in a way your fault?
a spell may not directly effect the free will of a person, if thats how you want it as the caster. A spell can be designed to completely overcome someone, however, this usually results in harm to the caster because they are not physically able to muster enough energy to complete the spell. you may not have intentionally caused harm but you shouldn't dabble in magick, before attempting any major spell like that you should have a good deal of practice, May I suggest using magick to send them a messenger, maybe a stag? they are great for giving messages