If a book falls off the shelf and no one hears it, did a ghost push it off? That’s something Mattapoisett Library’s Elizabeth Sherry wants answered.

“I’ve never experienced anything myself, but there were a couple of spooky incidences,” said Sherry. “This is an old library, so you never know.”

With Halloween coming up, Sherry wanted to look into some unexplained events that have happened at the library, such as items disappearing only to reappear in the locked attic.

From time to time, librarians have also unlocked the building in the morning to find books mysteriously lying on the floor in the stacks. Since a check is done of the entire building each night before closing up, there have been questions as to who or what caused the books to fall from the shelves.

Sherry called up S.P.I.R.I.T.S. of New England, a research team that investigates paranormal activity for answers. (S.P.I.R.I.T.S. stands for Supernatural Paranormal Investigations Research Initiative Truth Society.) In September, members of the five-person team did a specter stakeout of sorts, setting up electronic devices that are supposed to detect other worldly voices.

To clarify, investigator Jack Kenna explained, “No equipment anybody ever uses is designed to find a ghost. If there was, we’d find them real easy.”

The equipment includes infrared cameras, a shadow detecting laser beam to pick up on ethereal movement and audio recorders that S.P.I.R.I.T.S. investigators use to listen for electronic voice phenomenon (intelligible speech that may or may not be heard in the moment).

The S.P.I.R.I.T.S. crew conduct investigations for free and start by looking at possible natural causes for the supposed paranormal phenomenons reported by their clients.

“We don’t go in assuming a place is haunted,” Kenna said.

The investigators don’t even visit a home or business until the client has filled out a 10-page form. Then they sit down with the person or family and look at what is happening in their lives.

“Sometimes that can affect what’s going on,” said Kenna. “Even if we find that there’s a spirit there, it could be related to what’s going on with the family. It’s like spirits are attracted to drama, to the high energy.”

In some cases, though, it’s just bad wiring.

“Homes or buildings with high electromagnetic frequency can cause people to feel ill if it’s too high, to have hallucinations, to feel that someone is watching you,” Kenna said.

The team doesn’t dismiss ghostly activity though, and every member of S.P.I.R.I.T.S. has had personal experiences with the paranormal. They met and began discussing these encounters on an online forum for the Syfy TV show Ghost Hunters and eventually came face to face at an event hosted by the program.

With their shared interest and geography (Kenna, a New York resident, is the only one not in New England), the group officially formed in 2009. Since then, S.P.I.R.I.T.S. has conducted investigations in homes, historical building and even the USS Constitution. Several libraries have also invited the paranormal investigators, and now the Mattapoisett Library has been added to that list.

Sherry joined the investigation, which began at 8:30 p.m. one September night and ended around 1:30 a.m.

“Any place will be creepy at night, but there’s especially something about the library being empty and dark,” she said. “It was very spooky.”

Kenna said the hours of footage and audio recorded that night have not been analyzed yet, but Sherry said there was some activity on the “ghost radar.”

One piece of equipment picked up several words, according to Sherry, including “written” and “addition.” Addition could refer to the wing of the library that was added several years ago.

As the investigators prepared to leave, they asked any potential spirit in the building if it wanted them to go. The answer? “Entirely.”

Although it seemed to be ready for them to leave, Sherry said there was no ill will on either side, and Kenna said he has never come across anything demonic.

“Nor do I want to.”

Most overly active spirits can be handled, he explained.

“If you do find it’s a spirit in a home, deal with them like you do any other person. You have an unwelcome guest, you tell them to leave,” Kenna said. “There are some people who are just very content with living with them. To me it comes down to what do you believe in regards to your faith.”

Clients are often encouraged to deal with the drama in their lives and get their homes in order. They may be urged to consult a religious leader or a psychic medium.

Whether or not any of that will be necessary at the Mattapoisett Library is unknown. The team will give a lecture to discuss the findings on Oct. 27 from 7 to 8:30 p.m. That event is part of the Halloween-themed calendar at the library this month.

On Oct. 20, from 6:30 to 8 p.m., Luan Joly, author of “Dead Whispers” and founder of Whaling City Ghosts will discuss collecting audio recordings of “restless spirits.”

The Friends of the Library will continue their annual tradition of dressing up on Halloween and handing out candy in front of the building.

Sherry said the library will be decorated for the season and topical books, audiobooks, movies and podcast suggestions will be available to patrons.

And for those who may be reticent to step into the library for all of these spooktacular events, Sherry said the S.P.I.R.I.T.S. investigators told her that the library’s spirit seemed to be friendly.

“So nobody should be scared about coming to the library,” she said.