A chief constable had an affair with his assistant chief constable, resulting in her husband, who was also an officer, attacking him at home, a tribunal has heard.
Mike Craik, who has since retired from Northumbria Police, was alleged to have been in a relationship with Carolyn Peacock, a fellow high-ranking officer at the force at the time.
Giving evidence at a tribunal, the former head of legal services from the force alleged that Mrs Peacock's chief superintendent husband, Jim, punched Mr Craik at a barbecue after learning of the affair.
The tribunal in North Shields, North Tyneside, was convened after Denise Aubrey, 54, who worked in legal services at Northumbria Police for 20 years, was sacked for gross misconduct after she allegedly disclosed information about the affair.
She denies this and has instead accused her former bosses of "unfair dismissal following a protected disclosure, sex discrimination, disability discrimination, victimisation and harassment".
The names of those involved can now be reported after restrictions at the tribunal were lifted.