The Prisons and Probation Ombudsman has launched an investigation into the death of a woman who hanged herself in her cell six days after giving birth.
Michelle Barnes, 33, was found unresponsive at 11.11pm on 16 December 2015, the Ministry of Justice (MOJ) confirmed.
Staff at HMP Low Newton, near Durham, immediately attempted resuscitation but the new mother was pronounced dead shortly after.
Her partner, Charles Campbell, claimed that Barnes, who is believed to have had mental health needs, killed herself in her cell after being told by prison guards her daughter would be taken into care, The Guardian reported.
The mother of three, from Carlisle, was jailed for two years in July 2015 after pleading guilty to drug offences. She had recently been taken off suicide watch.
Campbell told The Guardian Barnes became "increasingly distressed" in the hours before she killed herself and feared she would never see her daughter again.
He also said that shortly before her death she told prison guards she was "planning to harm herself".
After giving birth via a caesarean section on 10 December, Barnes spent five days with her newborn child before being transferred back to the psychiatric unit at Low Newton prison.
It is alleged that on 16 December, the day of her death, Barnes had a conversation with a prison guard about an impending court case over the care proceedings for her baby and was told she "would never see her daughter again", The Guardian reported.
The court hearing was due to take place on 17 December, after which Barnes hoped to be transferred to a mother-and-baby unit (MBU).
Questions remain over why a woman with a history of psychological problems and who had expressed suicidal thoughts was not immediately placed under suicide watch.
Campbell told The Guardian it was "utterly bizarre" that she was not put back under suicide watch after a month of being taken off it.
He said: "I cannot understand why she was no longer on suicide watch. ... She had talked about harming herself but they didn't seem to take it seriously."
In a statement to BuzzFeed News, Prison Reform Trust director Juliet Lyon said wider questions need to be asked about whether prison is the right place for mothers with mental health needs.
Lyon said: "The ombudsman's investigation should consider the circumstances behind this tragic death and whether the prison service failed in its duty of care.
"Wider questions need to be asked about whether prison is the right place for women, particularly mothers and those with mental health needs.
"Despite government plans to do things differently, right now we still lock up our most vulnerable women in our bleakest institutions."
Under current policy, women who give birth while serving a custodial sentence are usually transferred to a prison's MBU for an initial period.
Earlier this month, David Cameron called for an urgent rethink of the way the prison system in England and Wales treats pregnant women and mothers with babies. Last year, 100 babies spent time living with their mothers in prisons.
A Prisons and Probation Ombudsman spokeswoman told BuzzFeed News that their investigation into Barnes' death "will identify lessons to be learned and make recommendations to help prevent similar deaths in future".
The statement said:
"We are very sorry to be informed of the death of Ms Michelle Barnes and extend our sympathies to her family, who we will involve in our investigation if they wish, and try to answer any questions they may have.
"Our independent investigation will aim to identify the circumstances of Ms Barnes' death at the prison and whether there were any failings in Ms Barnes' care at HMP Low Newton.
"Where possible we will identify lessons to be learned and make recommendations to help prevent similar deaths in future. We also share any findings with the Coroner to assist with his enquiries."
Fiona Rutherford is a reporter for BuzzFeed News and is based in London.
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