When Stacey Castor’s second husband, David, was found dead in 2005, the scene initially appeared to tell a straightforward story.

David had ingested antifreeze, and his death was classified as a suicide.

But investigators weren’t convinced.

The evidence inside the Castor home raised questions almost immediately. And as detectives continued digging, they began looking back at another unexpected death in Stacey’s past: that of her first husband, Michael Wallace.

What followed was an investigation involving forensic toxicology, DNA, fingerprints, an exhumation, digital forensics—and eventually, the near-death of Stacey’s own daughter.

The Death of Michael Wallace

Stacey Daniels met Michael Wallace as a teenager, and she would later describe him as the love of her life.

The couple married, had two daughters, Ashley and Bree, and built a life together in New York.

But by the late 1990s, the marriage had reportedly become strained. Michael and Stacey worked opposite schedules, money was tight, and there were rumors of problems within the relationship.

Then Michael started getting sick.

Family members later remembered him appearing weak, unsteady and swollen. His health seemed to deteriorate over time, but before doctors could determine exactly what was wrong, Michael died in 2000.

He was only 38 years old.

His death was attributed to a heart attack.

At the time, there was no murder investigation.

That would change years later.

A Second Husband Dies

After Michael’s death, Stacey eventually met David Castor. The two married in 2003 and created a blended family.

Then, in August 2005, David Castor was found dead inside the couple’s home.

Investigators discovered antifreeze near his body, and toxicology confirmed that David had ingested ethylene glycol, a toxic chemical commonly found in automotive antifreeze.

Initially, his death appeared to be a suicide.

But the physical evidence did not sit right with detectives.

A drinking glass contained David’s DNA around the rim, but the fingerprints recovered from the glass belonged to Stacey.

Then investigators found something even stranger inside the kitchen trash.

A turkey baster.

Testing revealed ethylene glycol on the baster, along with David’s DNA on the tip.

The question became increasingly difficult to ignore:

If David had poisoned himself, why did the scene contain evidence suggesting someone else may have helped administer the antifreeze?

Investigators Look Back at Michael Wallace

Detective Dominick Spinelli continued investigating David’s death, and within months, police began asking questions about Stacey’s first husband.

Michael Wallace had also become mysteriously ill before his sudden death.

Investigators eventually decided to exhume his body.

Years after Michael had been buried, forensic testing revealed something shocking.

He too had died from antifreeze poisoning.

The supposed heart attack was no longer simply an unexplained natural death.

Now police had two husbands connected to Stacey Castor who had both died after ingesting the same toxic substance.

And investigators were closing in.

Ashley Wallace Nearly Dies

In September 2007, Stacey’s daughter Ashley learned the truth about her father’s death.

Police told her that Michael Wallace had been poisoned.

Shaken by the news, Ashley called her mother.

Soon afterward, the two began drinking together at home.

The following day, Stacey prepared another alcoholic drink for Ashley. Ashley later recalled that it tasted terrible, but said her mother encouraged her to finish it.

She became extremely tired and went to bed.

The next morning, Ashley’s younger sister found her barely breathing.

Ashley was rushed to the hospital with a dangerous mixture of alcohol and medications in her system.

Nearby was a typewritten letter.

The letter appeared to be a suicide note written by Ashley.

And inside it was a confession.

The writer claimed responsibility for the deaths of both Michael Wallace and David Castor.

If Ashley had died, the note could have seemingly answered every question investigators had been asking.

But Ashley survived.

And when she woke up, she denied everything.

She said she had never murdered anyone.

She had not attempted suicide.

And she had never written the letter.

The Computer Tells a Different Story

Investigators turned to the family computer.

Digital forensic analysis uncovered multiple drafts of the supposed suicide note.

The timestamps became crucial.

The drafts had been created while Ashley was away at school.

That meant someone had been working on the confession before Ashley was ever found unconscious—and during periods when she could not have been the person typing it.

Investigators also noticed unusual wording throughout the note.

The writer repeatedly referred to antifreeze as “anti-free.”

Stacey had previously made the same unusual verbal slip during a police interview.

No single phrase could identify the author by itself, but combined with the timestamps and the other forensic evidence, prosecutors argued that the note was not Ashley’s confession at all.

It was an attempt to frame her.

The Trial of Stacey Castor

Stacey Castor went on trial in January 2009.

Prosecutors presented the jury with evidence from multiple forensic disciplines.

There was toxicology showing that David and Michael had both been poisoned with antifreeze.

There was physical evidence from David’s death scene.

There was DNA.

There were fingerprints.

And there was the digital trail left behind on the computer.

The defense attempted to create reasonable doubt by suggesting that Ashley herself could have been responsible for the deaths.

Ashley took the stand and denied murdering either man.

Stacey also testified.

Ultimately, the jury rejected the defense’s version of events.

On February 5, 2009, Stacey Castor was convicted of murdering David Castor and attempting to murder her daughter Ashley.

She was later sentenced to more than 51 years to life in prison.

Why Was Stacey Never Charged With Michael Wallace’s Murder?

Despite the forensic evidence showing that Michael Wallace had also died from antifreeze poisoning, Stacey was never formally charged with his murder.

By the time of her conviction, she was already facing what amounted to a life sentence.

Michael’s death had also occurred in a different county, meaning a separate prosecution would have been required.

Prosecutors had already been permitted to introduce evidence surrounding Michael’s poisoning during Stacey’s trial, and Ashley was reportedly reluctant to endure another emotionally exhausting murder case centered on her father.

The case was ultimately never brought to trial.

Stacey Castor died in prison in 2016 at the age of 48.

The Forensic Evidence That Connected It All

The Stacey Castor case is a powerful example of how several different branches of forensic science can work together.

Toxicology revealed the poison.

DNA and fingerprint evidence raised questions about how that poison had been administered.

An exhumation transformed a death once attributed to natural causes into a suspected homicide.

And digital forensics helped investigators challenge the authenticity of a supposed suicide confession.

Individually, each death or medical emergency came with an explanation.

A heart attack.

A suicide.

An overdose.

But once investigators began comparing the evidence, those explanations no longer made sense.

And what emerged was a much darker pattern.

Listen to the full episode of Forensic Tales for the complete story of Stacey Castor, the forensic evidence used against her, and the trial that made her one of New York’s most notorious convicted killers.

Listen to Forensic Tales:
https://www.forensictales.com

Support the show on Patreon:
https://www.patreon.com/forensictales

Patreon members receive full-length bonus episodes, ad-free episodes, exclusive merchandise, and more.

Follow Forensic Tales:
Instagram: https://www.instagram.com/forensictales
TikTok: https://www.tiktok.com/@forensictales
Facebook: https://www.facebook.com/forensictales