PHOENIX (AZFamily) — Cold case units in Arizona solved at least two major cases this week, bringing answers to families who waited years for closure.
In 1994, 13-year-old Christina “Tina” Plante vanished from a small Arizona town without a trace. A newly formed cold case unit reopened the investigation, using modern technology and reworking old evidence. The result: Tina was found alive.
“What stands out to me would be the fact that they never gave up. They, the family, the investigators, are kind of working together, the community,” Troy Hillman, a retired homicide detective, said.
Phoenix homicide case moves forward after arrest
This week, investigators also made progress in a 2023 death at Steele Indian School Park in Phoenix. Karissa Hamilton, 29, was found dead inside her car with the engine still running.
“Never did I imagine someone would have hurt her because she was a good person. She was a kind person,” Patricia Brienza, Hamilton’s aunt, said during a previous report.
The case moved to the cold case unit after detectives ran out of leads. During an unrelated arrest this week, investigators said Hamilton’s boyfriend made statements tying himself to her murder.
Andre Jermaine Gentry Nicholes, 29, was arrested March 27.(Maricopa County Sheriff’s Office)
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Technology and persistence drive breakthroughs
Hillman said modern breakthroughs come from multiple sources.
“That could be anything from social media, forensics like cell phones, your footprint on the internet,” Hillman said. “There’s also so many advancements in DNA, M-VAC system, rapid DNA testing.”
He said cold case review processes are essential.
“They highlighted the fact that the cold case review process was huge and when you don’t have that process in place, these cases are kind of collecting dust,” Hillman said.
“Cold cases are basically a puzzle. They’re investigations that have been worked once, twice, three times, even more and to be able to go back applying new technology, a new set of eyes, it’s kind of a game changer to work these kinds of cold cases,” Hillman said.
Investigators said anyone with information on any cold case, no matter how small, should come forward.
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