Depends where you live and which area you are in, you can always check with Google online
www.google.com and enter the keyword "paranormal investigator" and be sure to enter your city/town you live in. I hope they can help you, but not always they can work well.
My friend did contact the church priest when his house was haunted by some ghosts, so one day the priest showed up his house and read the bible book saying some words around his house. Later on, no more ghosts have been around his house for long times.
Believe it or not! That's strange...