Nov. 1, 2013 -- After being raised as Paul Fronczak, a 49-year-old Nevada man recently discovered that his entire identity, including his name, birth date and even who his biological parents are, was false.
After DNA testing revealed Paul Fronczak is not the baby stolen from a Chicago hospital nearly 50 years ago, Fronczak launched a mission to solve the two mysteries in his life: Who is he and what happened to the real Paul Fronczak.
"I feel kind of like an imposter because I am still using his birth certificate. Paul is out there," Fronczak told ABC News' Barbara Walters. "I have his birth certificate. ... I want to give it to him, and I want to find mine."
Stolen at Birth
The mysterious case of Paul Fronczak began at a Chicago hospital in 1964.
On Sunday, April 26, 1964, Dora Fronczak gave birth to a healthy 9-pound boy at Michael Reese Hospital. She and her husband, Chester Fronczak, named the baby Paul Joseph Fronczak.
The day after the baby's birth, a woman dressed like a nurse came into Dora Fronczak's room, looked at baby Paul and left without a word. Witnesses said the woman was seen elsewhere in the maternity ward several times that day and the day before. No one questioned her or raised any alarm.
At the time, Mary Trenchard Petrie was a 19-year-old student nurse working in the maternity ward, and was with Dora Fronczak the day after her delivery. Petrie said she saw the unknown woman in Fronczak's room.
"As I was leaving the room, a woman came into the room," Petrie told Walters. "The woman said to her, 'The doctor wants to see your baby,' and she said, 'Okay,' and handed the baby to her."
The woman in white was able to whisk baby Paul Fronczak out of the maternity ward, down several flights of stairs and out of the hospital. Petrie said 45 minutes passed before the baby was reported missing.
"Apparently she got in a cab and took off," she said.
For several hours, authorities frantically searched the hospital for the missing baby. At first, Dora Fronczak was not told that her baby was taken, but eventually, authorities came to the maternity ward to deliver the news.
"They told her, 'Mrs. Fronczak, your baby's been taken,'" Petrie recalled. "She cried a lot."
After learning that his son was stolen, Chester Fronczak appealed to the kidnapper through the press.
"I pray that she'll take care of the baby," Chester Fronczak told a reporter in 1964. "Return him."
Hundreds of Leads
During a massive investigation, Chicago police and the FBI distributed sketches and a description of the suspected kidnapper, who was described by witnesses as a woman around 35 to 45 years old, dressed in white like a nurse, but without the nurse's cap, and about 5-foot-4 with brown eyes and salt and pepper hair.
Police pursued hundreds of leads, including a woman who called to say she knew who took the baby.
"Bizarrely, she turns out to be the wife of an alleged drug kingpin who was apparently upset because her adopted child had been removed from her home by authorities," said Brad Garrett, ABC News contributor and former FBI profiler. "But she actually didn't know anything about the Fronczak case."
At the end of October 1964, Dora Fronczak received a phone call. The person on the other line said they would return the baby if the Fronczaks paid a $10,000 ransom. Police set up a sting with a bag stuffed with cut-up newspaper to resemble the money to capture the suspect.
"But it was a hoax," Garrett said. "They never had the Fronczak baby."
Months after Paul Fronczak was stolen, the nationwide search and relentless police investigation had come up with nothing.
A Little Boy Appears
Fourteen months after the kidnapping, a little boy, who was approximately 15 months old, was found abandoned in a busy shopping area 800 miles away from Chicago, in Newark, N.J.
Initially referred to as "Unknown Male Number One," the child was later placed with a foster family and named Scott McKinley. New Jersey authorities notified the FBI about the abandoned young boy.
The FBI asked for pictures of the boy's ears to compare with a picture of Paul Fronczak, who was photographed with only his left ear visible in the hospital after he was born. At the time, the shape of an infant's ear was thought to be as unique as a fingerprint.
"The FBI contacted my parents and said, 'We think we found…your son,' so my parents had to drive to New Jersey," Paul Fronczak said.
According to adoption files obtained by ABC News in the course of the 20/20 investigation, the Fronczaks believed the abandoned boy was baby Paul, but blood tests "were contradictory" and tests did not prove or disprove the boy was their son, so the Fronczaks were legally required to adopt him.
In June 1966, two years after baby Paul Fronczak was stolen, the couple took the boy home to Chicago, where they raised him as their own, thinking their nightmare was over.
"They brought me back and got me baptized immediately," Fronczak said.
The search for the origin of the abandoned child found in New Jersey ended and the Paul Fronczak case was closed.
A New Quest for Answers
Paul Fronczak was unaware of his kidnapping until he was 10 years old.
"I was looking for Christmas presents and snooping around the house, and I found all these boxes," Fronczak said. "It turned out it was a box of clippings and a bunch of cards and letters all about a kidnapping."
When he asked his parents about what he found, Fronczak said they said, "Well, you were kidnapped. We found you."
The discovery of his kidnapping became a big part of Fronczak's life and left him constantly wondering who he was.
But last year, Fronczak purchased an in-home DNA test at a CVS drugstore and while his parents were visiting convinced them to take the test. "It's something I wanted to do for a long time, but I never really had the nerve to ... ask my parents," Fronczak said.
When he received the DNA test results, Fronczak discovered that there was no remote possibility that he was the real Paul Fronczak.
"I don't know anything about myself," Fronczak said. "I don't know how old I am, my heritage, my birthday ... all these things that people take for granted."
Since finding out he was not the real Paul Fronczak, he admitted he has become obsessed with searching for the real Fronczak and finding clues about his own real identity. The FBI has also re-opened the case.
"My main goal for this whole project is to find the real Paul," Fronczak said. "My parents raised me, and they did a great job."
"I feel that if I don't do everything I can to help find the real child, then I'm not doing my job as a son."
ABC News Anchor Barbara Walters and Chief Investigative Reporter Brian Ross are investigating the case. Do you have any tips on this case? Click here to send them to ABC News.
You can also contact the FBI by emailing Chicago@ic.fbi.gov or calling 1-800-CALL-FBI. You can see another age-progression picture of the real Paul Fronczak at the National Center for Missing and Exploited Children.