Three people have been convicted of what a judge described as the “depraved, brutal and wicked” murder of a teenager 27 years ago.

Robert O’Brien, 45, Andrew Kelly and Donna Marie Brand, both 44, were found guilty of killing O’Brien’s 14-year-old girlfriend Caroline Glachan in West Dunbartonshire in August 1996.

Judge Lord Braid condemned the actions of the trio as he remanded them into custody at the High Court in Glasgow on Thursday afternoon following their convictions.

Caroline Glachan
Caroline Glachan was found dead after being attacked by her boyfriend and two other people in 1996 (Police Scotland/PA)

Miss Glachan’s family could be heard sobbing in court as the verdicts were delivered.

Prosecutor Alex Prentice KC told the court after the trio had been convicted: “Obviously this is a case of some age. The sense of the loss of Caroline Glachan, who was 14 and Margaret McKeich’s only child, has been immeasurable and has not diminished over the years.”

The jury unanimously convicted O’Brien, Kelly and Brand on Thursday afternoon after retiring to begin its deliberations on Tuesday.

Their trial was previously told Miss Glachan had been punched, kicked and struck repeatedly with bricks and other instruments to the head, and was either pushed or fell into the River Leven near Place of Bonhill, Renton.

Caroline Glachan murder trial
Donna Marie Brand outside the High Court in Glasgow during the trial (Andrew Milligan/PA)

Forensic pathologist Dr Marjorie Turner told the trial her cause of death was drowning.

The day Miss Glachan’s body was discovered by police – August 25, 1996 – was her mother Margaret McKeich’s 40th birthday.

Mrs McKeich told the media outside court on Thursday it was a “great day” to see her daughter’s killers convicted.

She said: “This is a day we never thought would happen.

“I would like to say a big thank-you to Detective Inspector Stuart Grainger and all of the police who worked on the case over the years.

Caroline Glachan murder trial
Andrew Kelly has been convicted of the murder of 14-year-old Caroline Glachan in 1996 (Andrew Milligan/PA)

“I just don’t know what to say. This has been a great day. I can’t sum up how I feel.

“It will not bring her back, but at least we know who was responsible is serving time because for the last 25 years, they’ve had their Christmases and birthdays, but my Caroline has been in the ground.

“This is a great day.”

During the 10-day trial, the court heard from several witnesses including Miss Glachan’s friend Joanne Menzies, who described O’Brien as a “bully”.

Mr Grainger, who led the investigation, said: “At the heart of this is a mother, a father, extended family and friends who have had to endure years of not knowing who killed Caroline.

Caroline Glachan murder trial
Caroline Glachan’s mother Margaret McKeich hailed the verdicts (Andrew Milligan/PA)

“Their lives changed forever the day Caroline was murdered, they were robbed of having a future with her, watching her grow from a young girl to a young woman. Her future was robbed the night she met Robbie, Donna and Andrew.

“For years this community has lived under a dark cloud, wondering if Caroline’s killers walked among them.

“Nothing will bring Caroline back or lessen the heartache her family and friends live with, but I hope that seeing those responsible paying for their crime offers them some level of comfort.”

O’Brien, Kelly and Brand will be sentenced on January 15 at the High Court in Glasgow.

The trio had denied the charge and had lodged a special defence of alibi.

When they were led down to the cells, a relative of Brand shouted: “I will fight to my last breath to get you out.”