Jeannie Williams still remembers the last moment she saw her 11-year-old son Jeffrey alive.
"My last vision I have of him is just sitting on the edge of the bed and him holding the iPad and playing a game," Williams told ABC's "20/20" in an exclusive interview.
Williams and her son had checked into Room 225 at the Blue Ridge Plaza Best Western Hotel in Boone, N.C., on June 7, 2013. They were planning to pick up Williams' daughter Brianne, 17, from a nearby science camp the next day.
But during the night the 49-year-old mother felt nauseous and hurried to the bathroom. First she sat with her head between her knees, but eventually moved to the floor and laid on her side.
"I knew where I was," Williams said. "I was on the floor, but my phone was plugged in by the bed. I knew I needed to get help... I remember [being] on the floor reaching and trying to get to the door to open the door, and I couldn't. I couldn't get it. And then that's the last thing I remember."
When Williams and Jeffrey didn't arrived to pick up Brianne, she called her father, who in turn called the hotel. When a clerk went to Room 225, she found Williams and Jeffrey.
"The next thing I remember is waking up in the hospital room," Williams said. "I couldn't talk."
After she awoke, Williams scrawled a note to her husband to ask about Jeffrey, "and that's when he told me that Jeffrey was with Jesus," she said.
Williams was shocked to learn she and her son had suffered from carbon monoxide poisoning. She was even more shocked to discover that a couple had died in Room 225 just seven weeks before their stay.
Daryl Jenkins, 73, and Shirley Jenkins, 72, were found dead in the same hotel room on April 16, 2013.
On 911 tapes from the day Jeannie and Jeffrey Williams were found unconscious, a hotel employee can be heard saying, "This just happened to us last month so please come help us... You don't understand, we just went through this."
When medics arrived at the hotel they, too, realized this wasn't their first visit to Room 225.
"And I look at my partner, and I said, 'If I'm not mistaken, that's the same room we had the last call in,'" said Mike Edmisten, an EMT for Watauga Medics in Boone. "Then we walk in, and we find two more bodies, same room. Stuff like this don't happen here. That's what everybody thinks. But it does."
Damon Mallatere, the hotel manager, chose to re-open Room 225 six weeks after the Jenkins' death. Mallatere is also the president of Appalachian Hospitality Management, the company that oversees the Blue Ridge Plaza Best Western, which is an independent hotel and not owned by Best Western.
Mallatere says authorities indicated to him the Jenkins died of natural causes. The room was re-opened before Watauga County medical examiner Dr. Brent Hall determined what killed the elderly couple.
"I don't believe that anybody that was in any way involved, whether it be the authorities or the contractors or my employees or myself should go to bed tonight and not feel responsibility," Mallatare told ABC News in an exclusive interview. "[But] I would never willfully hurt a guest if I knew that I could keep that from happening."