There are numerous individuals and groups who investigate and research the paranormal. These days it's hard to decide who you want to come in and help you resolve the problem. Some so called investigators will start right in, telling you all about how the spirits have taken over and how you need blessings and cleansings of your house. Many of those will offer to do it for a nominal fee. If you've encountered one of those, it's time to get someone else!

Once you've decided to contact someone, how do you decide who? There are several factors to consider, ask questions before you make the final determination. Like any contractor, it's best to get references. Ask for them. But keep these in mind;

A reputable investigator will come in to your home and begin by eliminating the commonplace things that might be responsible for what you've experienced.
The truth is, usually a creaky floor is a loose board; an orb in a photo is dust; strange voices are radio interference; and that thumping sound is a water pipe cooling. The point is often there is nothing paranormal at all. Any reputable investigator will tell you that. They will explain what is happening and show you the evidence. Not until these have been considered will any good investigator even begin looking toward the paranormal explanations

Reputable investigators do not make promises.
They can't give you a guarantee that they will rid your house of ghosts. It doesn't work that way, anyone who says otherwise has no idea what he's talking about, find someone else!

Reputable investigators work with others as consultants.
No one person or team is an expert on everything. Before you sign any investigator, ask for references and be sure to ask which other local groups or individuals they work with. Those who claim to go it alone or need no consultants are bad news. Find another team.

Ask about fees.
Reputable investigators charge no fee or pass along expenses to private clients. They also provide at no cost copies of evidence collected and summary reports of anything they find.

You as a client also have a decision to make.
There are several approaches to resolving your case. A reputable investigator will be able to advise you once a determination is made. Some people choose to live with their ghost, others want cleansings and blessings. Not all investigators do all these. That becomes a personal decision on the part of the client. Even though a particular group does not offer these, if they are reputable, they should be able to recommend someone who does if that is your choice.

Reputable investigators maintain client confidentiality to the level desired by the client.
Some want to maintain almost total secrecy; others want the world to know about their haunting. In either case the choice is up to the client and should be established early in the investigation.

Finally, some groups are very competitive.
They will attempt to put down others simply because they feel they are better. The truth is the paranormal is an inexact science. There are no absolutes so how can anyone claim to have definitive answers? Reputable groups work with, not against outside groups and investigators. Be cautious about any who make disparaging or unsubstantiated remarks about another group.