Think you have a ghost? You're not alone, judging by the amount of people who seek out paranormal investigators.
Part of the increase is due to their presence in pop culture, said Shamus Denniston, a paranormal investigator in Connecticut.
"There are many reality shows about paranormal activity," he said. "While they're helping to raise awareness, they can also create misunderstandings about what it is."
In 2010, he formed a group with other experienced individuals who perform paranormal investigations for no charge.
"The only time we charge a fee is when someone wants to do a tag-along to understand what we do," he said. "I consider this a labor of love. It's my way of helping people."
Denniston, who works full time as a college security officer, investigates homes, historic locations and even college campuses. He uses instruments like audio visual equipment, electromagnetic field detectors and night vision cameras.
"When someone says there's a spirit in the house, 90% of the time it's not the case," he said. "When it's true, it's usually a human spirit that's there for some reason and we try to find out."