Cherry Hill, NJ — On February 22nd, 1991, 22-year-old Dede Rosenthal vanished from her apartment without a trace.

There were no signs of a struggle, no broken locks, no fingerprints. Her front door was locked from the inside. Dinner was still warm. Her TV still playing. Only her shoes were missing.

The case baffled investigators.
The building was quiet.
And the girl next door — 10-year-old Jennifer Wertz — remembered nothing.

Police had no leads. No suspects. Just silence.
The case went cold.

But what no one knew at the time was that four years later, in the exact same apartment building — just one unit over — the darkness would return.

Only this time, the killer picked the wrong girl.

The Crime That Should’ve Worked—But Didn’t

On the night of March 12th, 1995, 14-year-old Jennifer Wertz was home alone, waiting for her mom to return from work. The doorbell rang.

A man in coveralls claimed there was a gas leak.
Jennifer was immediately on alert.

She’d been studying FBI profiling methods and criminal psychology since she was 11. Her bookshelves were stacked with case files, textbooks, and true crime manuals. She recognized the warning signs:

No ID badge

No company van

Vague explanations

Pressure to let him in

She played along.
Opened the door just enough.
Then, when he lunged—she didn’t run.

She started talking.

“My mom’s a nurse. She’ll be home any second.”
“Hey, your watch is cool. Is that a Navy issue?”
“Can I just grab my shoes first? It’s cold out.”

She kept humanizing herself, something she’d read in the FBI’s 1988 Behavioral Science Unit report: “Victims who assert identity can interrupt a predator’s process.”

She stalled.
She stayed calm.
She got close enough to hit the emergency dialer she’d programmed into the kitchen phone just weeks before.

Within five minutes, police were on the scene. Within ten, the man was in handcuffs.

The Serial Killer Next Door

The man was identified as Colin Maher, 41, a former HVAC worker with a sealed juvenile record and several dismissed assault charges.

When Cherry Hill detectives ran his prints, they got a hit — not from Jennifer’s case, but from a partial palm print found in Dede Rosenthal’s apartment back in 1991.

Maher had lived two floors below Dede. He’d worked as a subcontractor during renovations. And worst of all — his former employer confirmed he was “doing work” in the building the day Dede disappeared.

Inside Maher’s storage unit, police found:

Dede Rosenthal’s missing silver locket

A journal with meticulously documented stalking notes

Items belonging to two other missing women from the South Jersey area

Authorities now believe Maher was responsible for at least three murders between 1989 and 1995 — all in low-security apartment complexes, all targeting women living alone.

Jennifer Wertz: The Girl Who Solved the Case

What makes this case so chilling isn’t just the time gap — it’s that a 14-year-old girl cracked it wide open, using nothing more than her instincts and what she’d learned from studying criminal behavior.

She wasn’t lucky.
She was prepared.

Jennifer’s calm under pressure not only saved her life, but also led directly to solving one of Cherry Hill’s oldest cold cases.

“I just kept thinking — what would a profiler do?” she said later in an interview.
“If I panicked, I was dead. So I didn’t.”

Aftermath and Legacy

Colin Maher was convicted of two counts of murder and one count of attempted abduction. He is currently serving life without parole.

The Rosenthal case was officially closed after 34 years.

Jennifer Wertz became the youngest civilian to receive a commendation from the New Jersey State Police for aiding in a cold case resolution.

She later went on to study forensic psychology at Georgetown University.

Today, Jennifer works as a consultant for youth self-defense and trauma-informed awareness programs, helping other teens recognize red flags and trust their intuition.