Suppression of Vital Information Leads to Personal Liability

Mellen v. Winn, (9th Cir. 2018)

Susan Mellen was convicted of first-degree murder in June 1998, based largely on the testimony of June Patti. Patti claimed Mellen confessed privately to her, even though others had also confessed to the murder. Seventeen years later, Mellen was declared factually innocent and released from prison. Mellen then sued the Los Angeles Police Department detective who investigated the murder and claimed Mellen was the killer.

In the trial that resulted in Mellen’s initial conviction, the detective withheld a statement from Patti’s sister, Laura Patti, who was a police officer at the time of the investigation. June Patti had been a paid informant, though the police no longer used her services because she was unreliable. In her statement, Laura Patti told the detective her sister June was “the biggest liar” she had “ever met” in her life and she did not “believe anything says.”

The trial court granted summary judgment to the detective. However, the appellate court reversed, ruling the jury should have been told about the police officer sister’s statements.

Though the usual Brady/Giglio claim arises in a criminal case where the defendant seeks to exclude evidence or reverse a conviction, in rare and egregious cases the investigating officer may be civilly liable for withholding evidence. To successfully bring a claim against the individual officer, the plaintiff must show:


  • The investigator failed to disclose to the prosecutor and defense known evidence that was favorable to the defendant.
  • The investigating officer acted with deliberate indifference to or reckless disregard for the defendant’s rights or for the truth.
  • Withholding the evidence harmed the defendant.

It was an easy conclusion for the court: Laura Patti’s testimony about her sister’s habitual dishonesty, had it been disclosed by the detective, could have changed the outcome of the trial, and the detective’s suppression of vital information was harmful to Mellen. Moreover, the law was clearly established at the time of the detective’s Brady/Giglio violation, so she could not benefit from qualified immunity.

Ken Wallentine

KEN WALLENTINE is the Chief of the West Jordan (Utah) Police Department and former Chief of Law Enforcement for the Utah Attorney General. He has served over four decades in public safety, is a legal expert and editor of Xiphos, a monthly national criminal procedure newsletter. He is a member of the Board of Directors of the Institute for the Prevention of In-Custody Death and serves as a use of force consultant in state and federal criminal and civil litigation across the nation.

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