AN “obsessed” former police constable has been convicted of stalking his estranged policewoman wife who he caught having sex with an inspector in a Screwfix car park.

On Monday, a jury at Liverpool Crown Court found father-of-two Gavin Harper, 45, guilty of the aggravated stalking of Stephanie Glynn, 40, causing her serious alarm or distress between December 2020 and February 2021.

Jurors could not reach a verdict on the allegation that Harper also unlawfully wounded Andrew McLullich, 42, at the Screwfix car park in Birkenhead, Wirral.

Prosecutors will return to court on April 2 to announce whether they will seek a retrial on the outstanding count.

The Crown said the security officer subjected Ms Glynn to “obsessive, intrusive and unwanted behaviour” including spying on her, secretly bugging her car, listening into her conservations, tracking her whereabouts and taking her phone without her permission.

Harper discovered the late night Screwfix tryst after it was said he placed a tracker underneath Ms Glynn’s vehicle.

The defendant and Ms Glynn met as Merseyside Police officers and were in a six-year relationship before they married in 2018.

But Ms Glynn left the family home in December 2020 after she grew close to her work mentor Mr McLullich and the prosecution said the defendant could not accept the marriage breakdown and became “obsessed with catching her in the act”.

Ms Glynn and Mr McLullich were naked from the waist down in the back of the inspector’s vehicle when Harper crept up and filmed them at the window with his mobile phone.

Glynn, now divorced, was said to be “sickeningly anxious” as a result of the defendant’s campaign of behaviour and told the jury she “constantly looked over her shoulder”, had changed her routes to work and had undergone counselling.

Ryan Rothwell, prosecuting, said that Harper knew what he was doing was wrong, not only because of his police background but also because he was warned about his behaviour on a number of occasions including from Ms Glynn who told him he was “unhinged”.

The Crown alleged the defendant “rained” punches on the married inspector after he opened the rear passenger door of the vehicle.

It was then said Ms Glynn pulled Harper away as Mr McLullich managed to get out of the car and pull up his tracksuit bottoms.

The prosecution further alleged that Mr McLullich tried to stop Harper retrieving a tracker from underneath Ms Glynn’s car and the defendant responded by striking him, possibly with a torch, to the top of his head.

Harper denied causing cuts to Mr McLullich’s head with, or without, a torch.

Harper also denied self-inflicting facial injuries after he left the scene at Screwfix and said Mr McLullich, who has since left Merseyside Police, did not have a head injury when he drove off.

His barrister, Suzanne Payne, told the jury: “Up until October 2020 Gavin Harper thought he was in a good marriage and they were going to have a family.

“Then his wife started acting out of character and he wanted to know what was going on.”

Giving evidence Harper said he did not have violence on his mind when he arrived at the car park and just wanted “undeniable proof” of the affair which Ms Glynn had persistently denied.

His intention was to pass the video on to police as evidence of two serving officers having an inappropriate relationship during Covid, he said.

Harper, of Ailsa Road, Liscard, Wirral, said Mr McLullich was the aggressor and it was he who started punching him from inside of the vehicle and he responded with “three, four” punches in self-defence.

He said he did not have the energy to react any further and was punched again on the floor by Mr McLullich who had “leg-sweeped” him before he said Ms Glynn kicked him to the side of his body with her socks on.

Harper said he later made a comment about the size of Mr McLullich’s penis and was met with further blows.

Jurors found Harper guilty of aggravated stalking by a 11-1 majority verdict.

Harper was granted conditional bail ahead of his next court appearance but was told by Judge David Potter he faced an immediate custodial sentence for the offence he had been convicted of.