Four former and serving ambulance staff and a hospital worker have been arrested over the death of a man outside an A&E department earlier this year.
A 44-year-old female member of staff from Walsall Manor Hospital in the West Midlands was arrested today on suspicion of manslaughter by gross negligence and misconduct in a public office.
It follows the arrests this week of four people aged 26, 34, 45 and 53, on suspicion of the same offences.
The woman has now been bailed while West Midlands Police inquiries continue.
Of the four other people arrested, one is a serving member of staff with West Midlands Ambulance Service (WMAS) - and is currently suspended from operational duties.
The remaining three people are all former employees of the ambulance service.
All four are currently on police bail.
The arrests are in connection with the death of 47-year-old Carl Cope, of Bloxwich, who collapsed and died outside the hospital's A&E department on June 23 this year.
A post-mortem examination revealed Mr Cope died of a heart attack.
Chris Kowalik, ambulance service spokesman, said: "We are co-operating fully with West Midlands Police.
"One of the people arrested is a serving member of staff who has been suspended from operational duty and we understand that three former members of WMAS staff have also been arrested as part of the investigation."
In October this year, the hospital trust also concluded its own internal investigation into what health bosses called a "serious incident".
Richard Kirby, the trust's chief executive, apologised to Mr Cope's family.
He said: "We are committed to supporting staff to ensure that we keep our promises to patients that they should feel welcomed, cared for and in safe hands."
The police investigation into the circumstances of Mr Cope's death continues.