Knowing and looking for the signs of paranormal activity is the best way to determine if you are dealing with a true entity. Keeping a journal makes it easier to document the suspicious activity.
When investigating paranormal activity, keeping a journal gives a sense of control and helps you decide if there are any rational explanations for the phenomena. Shadows can be mistaken for human figures, for example, and noises coming from a furnace or plumbing can be mistaken for footsteps. No matter how smart an individual is, he can easily be fooled by his senses. The family pet can also be a great tool in investigating paranormal activity. Dogs and cats have extremely heightened senses and may react to an unseen presence. It is important to rule out any natural explanations before attempting to call in a professional team.
Several websites have listings of groups who investigate paranormal activity for free. Some of these groups are members of recognized organizations such as The Atlantic Paranormal Society. Never pay for services related to paranormal activity. Only contact these groups if you have eliminated all other possibilities and feel like you or your family may be in danger. The presence of a negative entity may require the help of a member of the clergy.