More than two decades after the bodies of a woman and 10-year-old boy were found in separate states, each discarded along the side of a highway, officials announced Tuesday a DNA analysis identified the victims as a mother and son -- and helped authorities to elicit a confession from their killer.

The identity of the woman was revealed Tuesday to be Myoung Hwa Cho. Cho was suffocated before her nude body, bearing ligature marks around the wrists, was discovered dumped in the woods along Interstate 85 in South Carolina in May 1998, The Spartanburg County Sheriff's Office said in a news release.

In September 1998, 215 miles away from where Cho's body was dumped, the remains of a young boy were found under a billboard by workers mowing grass along Interstate 85 in Mebane, North Carolina.

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The Orange County Sheriff’s Office in North Carolina said its own news release that, after trying other forensic analysis techniques -- including even creating a bust of the child -- the department used the analysis of an online DNA database to identify the child, who was a first-generation, biracial Caucasian and Asian.

“I always kept the case file box under my desk, where it was purposefully in my way. Every time I turned, I hit it with my leg. I did this so the little boy couldn’t be forgotten," Orange County Sheriff's Maj. Tim Horne, who worked the case from the beginning, said in a statement.

After identifying the race of the boy, the agency enlisted the help of a consultant, Dr. Barbara Rae-Venter. Rae-Venter, whose work led to an arrest in the Golden State Killer case, matched the child's DNA to DNA from a close relative who had submitted information to an online DNA database. After contacting the relative, investigators learned the boy's name: Robert "Bobby" Adam Whitt. They soon found out Whitt's mom -- who had disappeared the same year as her son -- was also dead.

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With help from the National Center for Missing and Exploited Children, authorities in North Carolina said an unidentified female matching the search criteria was located in Spartanburg County, South Carolina. After contacting officials there, the DNA of the victims were compared and soon proved to be mother and son.

Authorities in South Carolina used fingerprints, with the help of the Korean National Police and INTERPOL, to identify the woman as Myoung Hwa Cho.

“This case is an example of dogged determination of investigators who refused to give up," Orange County Sheriff Charles Blackwood said. "The efforts of Major Tim Horne and the entire investigation division were exemplary.”

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Investigators then were led to Cho's husband and Whitt's father who is currently serving federal time for unrelated convictions, according to FOX Carolina.

The husband confessed to the murder of both victims within several months of each other in 1998, according to police.

Officials said that it does not appear that either killing took place in Spartanburg County or Orange County, so the man's identification is being withheld until authorities can determine where the mother and son were killed and a prosecutorial decision can be made.

Authorities commended the work of both offices in utilizing new technology to finally crack the cold cases. Last year, detectives across the country said they were able to locate suspects in 28 cold cases after uploading crime scene DNA to GEDmatch.com, a public genealogy website.

“With technology what it is today, crimes that have gone unsolved before are now ripe for resolution," Blackwood said.

Fox News' Robert Gearty contributed to this report.