'People Magazine Investigates' : Where Are the Surviving Members of JonBenét Ramsey's Family?

Since the strangled body of 6-year-old JonBenét Ramsey was found in the basement of her family’s Boulder, Colorado, mansion nearly two decades ago, her family has tried to continue with their lives.

The mystery surrounding her death is the focus of the upcoming People Magazine Investigates episode “JonBenét: The Untold Truth,” which airs Monday night at 10 p.m. ET on Investigation Discovery.

• For more on the case of the JonBenét Ramsey case, watch “JonBenét: The Untold Truth” on our 10-part true crime show, People Magazine Investigates, airing Monday night at 10 p.m. ET on Investigation Discovery.

JonBenét’s parents, John and Patsy, lived under an “umbrella of suspicion” in connection with her death, the Boulder police chief said at the time. But they maintained their innocence – even appearing on CNN within days of the killing to say they had nothing to do with it. They have never been charged in the case.

“The longer it goes, the harder it gets,” John told PEOPLE in 2012.

WATCH: Three Things To Know About JonBenét Ramsey & The Latest On The Hunt For Her Murderer

Patsy died in 2006 from ovarian cancer and in 2012, John, 72, remarried and runs a promotional marketing company. He splits his time between Charlevoix, Michigan (where the family had moved when JonBenét’s brother, Burke, reached high school), and Las Vegas.

“I don’t know now. I don’t dwell on it, it’s not critical to my future,” John previously told PEOPLE of his daughter’s mysterious death. “I would like to know.”

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Burke, who was 9 at the time his sister died, graduated from Purdue University in 2010 with a degree in computer and information technology.

A two-part CBS series broadcast in September featured a panel of experts who advanced the theory that Burke was responsible for his sister’s death, but theorized her death was an accident.

Ramsey family attorney L. Lin Wood responded by filing a $150 million libel lawsuit against Dr. Werner Spitz, a forensic pathologist quoted on the series who repeated his accusation against Burke on a Detroit radio show. Wood has promised a libel suit as well against CBS, which issued a statement standing by its broadcast.

• Watch the People Magazine Investigates After Show, on the new People/Entertainment Weekly Network (PEN). Go to PEOPLE.com/PEN, or download the PEN app on Apple TV, Roku Players, Amazon Fire TV, Xumo, Chromecast, iOS and Android devices

In 2008, John, Patsy and Burke were formally cleared of any involvement in the child’s death.

Then-District Attorney Mary Lacy wrote a letter to John, saying that DNA evidence cleared the trio. She apologized to the family for the scrutiny the family lived under as a result of the case.

However, current District Attorney Stan Garnett has said Lacy erred in writing the letter.

“I didn’t feel the exoneration was warranted based on the state of the evidence and the complexity of the case. And I also thought it was a very unusual thing to do in a case where there had never been any charges filed,” Garnett recently told PEOPLE.

• Reporting by VICKIE BANE and JEFF TRUESDELL