If only the sandmen before them were just ordinary creature that was capable of speaking, it will be a lot easier for them to acquire information.
They could just simply use some Elixir of Truth and Lies and the other party will spill the truth without any delay.
But unfortunately, that is not their case. The two sandmen before them are not capable of speaking at all.
All they could utter are incoherent mutterings such as 'roar'. So rather than trying to get the information they need out from their mouth, the group of warlocks opted to use another method instead
They will be using the Servant Spell.
This spell works in messing up the psyche and will of its victim. Contorting facts and lies. Putting its victim into a servant mentality.
Once put under this spell, one will have no choice but to follow whatever demand or order that was given to them by the warlock or sorceress that conjure the spell.