Durham Police faces legal action over the death of a woman who plunged from a viaduct, seconds after she was freed from handcuffs.
Janice Clark, 50, was on the wrong side of safety barriers on Hownsgill Viaduct, near Consett, when officers were called to assist in August 2017.
She was locked onto the barriers with handcuffs, but was released when she said she no longer intended to jump.
However, seconds later the former army captain fell to her death.
Her family claims the officers should have waited for the fire brigade to arrive to attach her to a harness before releasing her.
'Massive, tragic error'
It said: "The police were warned by members of the public who were on the scene not to remove the handcuffs."
The family said it was not seeking to take action against the individual officers involved though, because it accepts the officers "have been through enough".
"It is not for money either. It was a massive, tragic error and we don't want it to happen again," a family spokesman added.
The Independent Office for Police Conduct (IOPC) investigated and found no action should be taken against the officers involved.
An inquest into the death recorded an open verdict because it was not clear whether Miss Clark, who had a history of mental illness, accidentally fell or jumped.
A Durham Police spokeswoman said: "This was an extremely tragic incident for everyone involved and our thoughts remain with Janice's family and friends.
"We welcome the findings of the IOPC investigation, but given the pending legal action, it would be inappropriate for us to comment further."
The IOPC said: "After a thorough examination of all the evidence, we did not consider there to be an indication that any police officer involved in this incident may have behaved in a manner that would justify the bringing of disciplinary proceedings or committed a criminal offence."
A protective steel fence was fitted to the 155-year-old grade II-listed viaduct in 2012 after a spate of suicides, which peaked at one every two weeks in the first six months of 2011.
The former railway bridge is used by walkers, riders and 250,000 cyclists a year following the C2C cycle route which crosses it.