The next day Wilkerson's son called the police -- his mother had vanished from her home during the night.
When investigators asked Scott if he recalled anything suspicious, he remembered his missing Blackberry.
"I began to talk and I said, 'You know, I think my Blackberry is in Mary's car,' and they said, 'Oh my God, that's all we need," Scott told "Good Morning America."
Using the Blackberry's signal as a homing beacon, police worked with U.S. marshals and were able to track down Mary's car on Tuesday. They found it in an alley about eight miles from her home.
Then they heard noises coming from the trunk.
"We started to pry the trunk, that's when I heard her voice," Susquehanna Township police chief Rob Martin said. "That's when I heard her saying, 'Get me out of here.'"
The three days stuffed in her trunk with no food or water took its toll on Wilkerson.
"She was conscious and able to talk, but certainly in an unhealthy condition," Martin said.
Scott, a retired clinical psychiatrist and Penn State University professor, told local newspaper The Patriot-News that even though Wilkerson "was scared to death," he was "surprised with her mental state."
"She was cognitive, communicative," Scott said. "Not a lot of people could go through what she went through."
Wilkerson was hospitalized for dehydration and bruises but returned home Thursday.
Later, she reportedly told friends a group of masked men broke into her home and kidnapped her.
No Suspects, No Official Motive
According to The Patriot-News, Wilkerson told Scott the men demanded money.
Police have no suspects and are still investigating motive.
Another neighbor, Andrea Jackson, told The Patriot-News it was "unexplainable" because Wilkerson did not flaunt wealth.
"She doesn't have anything extravagant in her house," Jackson said. "She's very frugal. I don't know what they expected to get from her."
Scott said he's just happy his Blackberry was in the wrong place at the right time.
"It is a blessing in disguise in many ways," he said. "I am very thankful for that."