it helps to be a bit sympolic when describing the vision. Always give it a dream like quality. Also use imagery and symbolism. If the killer is a evil merchant illusionist, you can details that fit his description (tall, dark hair, balding, brite eyes, etc) while providing a description that makes them guess.
For eample, if the killer is a local noble or rich merchant who is evil, heartless, cruel, tall, middle aged and raises falcons, this might do: GM, "you see the victem standing by the bath, a dark shadow of death hovers him, causing primal fear to fill you heart and bring yur mind to the brink of madness. The cloaked shadow of death looms over poor Mister Butterbur, its long scyth causing an adible shrik as it slashes through the air...just as the blad pieces his side, a tall drk man that is more black hearted bird, all sharp angles and hatred, steps from the shadows death and plunges the murder weapon into Butterbur, whose dying scream is drowned out by the rising roar of deaths vengful howl...all fades to black, and you pull yourself from the trance before following the reaper into the realms of the dead, a place of madness for all mortals..."
information delivered, now the players will drill the vision holder (uh, thats actually you Mr. GM lol) with questions. In time, when one of the PC's is visiting their erstwhile advocate and supporter of their investigation, be sure to walk them through his avery. Don't point out there are only falcons in it, though feel free to make the players curious enough to ask when you note the foot thick layer of feathers and remains that litter the floor under the eaves of the trees...
additionally, assume the places and powers were the information is drawn are VERY REAL. Planes of dead, demons, elemental hells, etc: all posibly tapped into by the divination. Our diviner listens to the voices and echos of voices, but to get to near those with those voices...there in lies story hook after story hook. I assume your cleric would feel awful if possessed, or if his mond was stolen and used for evil, or just help prisoner, or if the clerics mind was swapped with a demons and his...well, you get the point.
The best tool to resolve these sorts of battles when the occur is the will contest table in the channeling companion.
never let a spell stand in the way of a good story. incorperate it!