Forensic Files - Season 8, Episode 24 - Nailed - Full Episode

FilmRise True Crime・2 minutes read

A key witness, Helena Greenwood, was murdered before testifying at a trial, with evidence pointing to David Paul Frediani as the culprit despite his denials. Frediani was ultimately convicted of Helena's murder after DNA evidence linked him to the crime.

Insights

  • Helena Greenwood, a respected research scientist, was tragically murdered before testifying at a criminal trial. Her husband, Roger, was initially suspected but cleared due to a confirmed alibi, leading to the arrest and conviction of David Paul Frediani, who stalked the couple and left crucial forensic evidence at the crime scene.
  • Despite Frediani's denial of murder, DNA evidence under Helena's fingernail, not matching her own, led to his arrest. His meticulous planning, including wearing gloves to avoid leaving fingerprints, was undone by a car accident days before the murder, proving his presence in San Diego. The case highlights the importance of forensic evidence in solving crimes and how Helena's scientific work ultimately contributed to convicting her killer.

Get key ideas from YouTube videos. It’s free

Recent questions

  • Who was Helena Greenwood?

    A research scientist murdered before testifying at a trial.

Related videos

Summary

00:00

Murder of Scientist Helena Greenwood Unsolved

  • A key witness, Helena Greenwood, a research scientist, was murdered weeks before testifying at a criminal trial.
  • Helena was described as brilliant, quiet, honest, and a hard worker, with a Ph.D. in microbiology and marketing skills.
  • In 1984, Helena was sexually assaulted and robbed in her home in Atherton, outside San Francisco, while her husband was away.
  • The assailant entered through a kitchen window, leaving fingerprints on a teapot found outside by a friend.
  • A year later, David Paul Frediani, arrested for exposing himself, was found to match the fingerprints on Helena's teapot.
  • Frediani initially denied involvement but confessed when confronted with the evidence.
  • Despite Helena's inability to positively identify Frediani, the fingerprints on the teapot were crucial evidence for the prosecution.
  • Before her murder, Helena had moved to San Diego for a new job at Gen-Probe, focusing on DNA-based disease diagnosis.
  • Helena was found murdered at home, with signs of a struggle and strangulation, but no physical evidence was left behind.
  • Roger, Helena's husband, was initially suspected but was cleared when his alibi was confirmed, and he was at work during the murder.

10:29

"Frediani's Fatal Mistake: DNA Evidence Convicts Him"

  • Roger Franklin, Dr. Greenwood's husband, informed the narrator of his wife's murder in San Diego, where they had moved after a sexual assault trial.
  • Dr. Greenwood's purse, car keys, and credit cards were found near her body, indicating no robbery had occurred.
  • David Paul Frediani, accused of Helena's sexual assault, was out on bail during her murder but claimed to be in San Francisco.
  • Prosecutors presented evidence linking Frediani to Helena's sexual assault, including fingerprints and serological evidence.
  • Frediani pleaded no contest to the assault charges but maintained his innocence in Helena's murder.
  • DNA testing using Polymerase Chain Reaction (PCR) technology revealed DNA under Helena's fingernail not matching Dr. Greenwood's, leading to Frediani's arrest.
  • DNA evidence from Helena's fingernail and stockings, compared to Frediani's blood sample, had odds of one in 23 billion of not being his.
  • Frediani was arrested for first-degree murder, believed to have killed Helena to end the sexual assault case against him.
  • Frediani stalked the couple, learning their schedules, and waited for Helena outside her home, wearing gloves to avoid leaving fingerprints.
  • Frediani's mistake was a car accident days before the murder, proving he was in San Diego, leading to his arrest and conviction.

20:15

"Gloves, Evidence, Conviction: Helena's Tragic Story"

  • Frediani, believing gloves would protect him, left crucial forensic evidence behind, which Helena unknowingly grabbed, possibly leaving evidence to identify her killer.
  • Despite Frediani admitting to sexual assault but not murder at trial, he was convicted and sentenced to life in prison. Helena Greenwood testified against him, leading to his conviction, although tragically, he later tracked her down and killed her. Helena's work in science ultimately helped in convicting her killer.
Channel avatarChannel avatarChannel avatarChannel avatarChannel avatar

Try it yourself — It’s free.