In 2013, Brett Mugglin and Mark Hartman moved into their new off-campus housing in preparation for their senior year at Ohio State University.
The house was huge, and eventually it would house 10 of Mark's friends, but in the early stages of the move, there were just three: Mugglin, Hartman and another, MJ.
After a few days in house, they woke one morning to find every door open in every room — room doors, the dishwasher, the fridge, dryer, washing machine, oven and microwave. They joked it must have been a ghost.
"We had been telling everybody the story of the ghost in our house coming in and opening all our cupboards and the microwave and oven and all this stuff," Hartman told college newspaper The Lantern at the time.
Hartman thought it may have been a college prank, he told the Criminal podcast earlier this month. Mugglin thought maybe he had been sleep walking.
But then they heard a series of "weird noises like dings and alarms" coming from downstairs. They decided to investigate.
"We each grabbed a baseball bat, or a knife, and we were going through all the rooms, opening closets. One of us would have the baseball bat ready to jump at anything that came out of the closet."
They didn't find anything — until they reached the basement...They discovered a locked door no one had a key to — the sounds were coming from inside.
"A few times, when my roommate Brett was down there, he would hear noises," Hartman told ABC News at the time.
"But, when he tried to turn the handle on a door located in the basement, it was always locked."
The men thought it was probably a utility closet.
For weeks, strange occurrences started to plague the house — drawers were mysteriously opened in the kitchen and bathroom, lights were turned on and noises kept coming up from the basement.
One day, when Mugglin was downstairs fixing the power, he had a strange encounter. He came across a man he'd never seen before.
"He was like, 'I was wondering when I would get to meet the people who live here'."
The pair introduced themselves, had a brief conversation, then parted ways. The man said his name was Jeremy.
"Later that day a bunch of us were hanging out and Brett's talking to the downstairs lodgers. He said, 'hey, I met your roommate Jeremy today'.
"They were like, 'we don't have a roommate named Jeremy'."
So they called the landlord, who called the police.
"The landlord and police pried off the door handle and, inside, we found a liveable bedroom with photos, a TV and clothes," Hartman said.
"What was inside astonished everyone — a secret world packed with somebody else's belongings. Pictures of a man with friends and family. An unmade bed. Books. A secret human living in their house."
What the guys didn't realise was that the basement was the home to a secret bedroom and someone had taken it upon themselves to board for free. The room included a toilet and bathroom.
They person was able to sneak through a side door that led to the basement.
In a creepy twist, Mugglin identified the man in the photos as Jeremy.
"He was a really nice guy," Mugglin told The Lantern.
"I feel bad for him. It's just, he wasn't supposed to be living there ... It's funny now, but it potentially could have been extremely dangerous given that some random guy had a key to our house and was just living in our house without anyone knowing."
Jeremy wasn't home at the time of the discovery but a few days later the boys discovered most of his belongings had disappeared.
They later discovered Jeremy's cousin had lived in the house the year prior, which is how he initially got access to the house. He was also a student at the college.