A police sergeant who failed to properly assess a "vulnerable" woman in his custody who later died is guilty of gross misconduct.
Jason Marsden "lost control" while dealing with Kelly Hartigan-Burns at Blackburn's Greenbank Police Station in 2016, an independent panel disciplinary said.
Ms Hartigan-Burns, who had a history of mental illness, self-harm and alcohol misuse, was found unresponsive in her cell on 4 December and later died at Royal Blackburn Hospital.
She had been arrested over an alleged assault the previous day.
Mr Marsden did not ask a medical expert to examine Ms Hartigan-Burns's condition despite her earlier trying to take her own life.
He did not read the deceased her rights, spoke to her in an abrupt manner and did not explain detention procedures.
Mr Marsden also deliberately bypassed questions on a computer system designed to flag up risks to detainees and ignored police records showing she had tried to kill herself.
At the time of her arrest Ms Hartigan-Burns, 35, was intoxicated, under the care of a psychiatrist and had prescription medication on her person.
An independent panel ruled that Mr Marsden, who did not attend the proceedings, breached professional standards and would have been sacked had he not quit his job just weeks before the hearing started.
Representing Mr Marsden, Sarah Barlow said it was an isolated incident in his 27-year career.
Lancashire Police's Temporary Assistant Chief Constable Russ Procter offered the force's "sincere condolences" to the deceased's family.
It would be "inappropriate and unfair... to comment any further" due to the "ongoing coronial and civil proceedings", he added.
Carolynn Gallwey of Bhatt Murphy, which represents the family, said: “While this outcome offers the first vindication finally of the family’s concerns that proper care was not taken of Kelly, it is nothing sort of appalling that they have had to wait almost five years to hear it.
"They now look forward to the inquest next year, which they trust will fully expose and interrogate the evidence for all to see.”
Speaking after the ruling Ms Hartigan-Burns's mother, June Hartigan, said: "Taking over five years to get to this point is ridiculous, it is very painful finding out facts now.
"This hearing has helped the family to get nearer to the truth about what happened, it should ensure this never happens to others.”