The father of a teenager murdered on an Ayrshire beach has demanded answers after it emerged that two of his son's killers were under the supervision of social services at the time.

Kayden Moy, 16, was fatally stabbed on Irvine beach in May last year following a clash between rival groups of youths.

Two of the three boys jailed for the fatal attack last month were under supervision.

And Paul Moy, who has met First Minister John Swinney to discuss his concerns, said he believed his son might still be alive had action been taken by South Lanarkshire Council.

Moy, from East Kilbride, told BBC Scotland News: "I really believe Kayden's death could have been prevented.

"There have been so many chances where this could have been stopped and it wasn't.

"They have been allowed to repeatedly re-offend and it has cost my son his life."

A council spokesperson said: "This has been a tragic event, and our profound sympathies continue to go out to Kayden's loved ones."

Cole Turley, 18, and Jay Stewart, 19, were sentenced to life imprisonment and ordered to serve a minimum of 16 years for Kayden's murder.

A third boy - who was 15 at the time and cannot be identified for legal reasons - was detained for at least 14 years.

Two of the boys were known to social services and Moy, 38, said South Lanarkshire Council had "serious questions to answer".

Jay Stewart had previous convictions and matters dealt with by the Children's Hearings.

He had two convictions, one for various charges including possession of a knife in a public place and possession of a metal pole as part of threatening and abusive behaviour.

At the time of the murder, he was on a structured deferred sentence for that case.

His second conviction, on 22 April last year, was for possession of a machete in a public place.

Stewart was made subject to a community payback order in that case, just four days before Kayden's murder.

Separately, the 15-year-old was placed on a compulsory supervision order in January last year.

A Compulsory Supervision Order (CSO) is a legal order made by a Children's Hearing or a sheriff in Scotland.

It requires a child or young person to follow specific rules and forces the local authority to provide ongoing support, care, and social work supervision.

Moy said: "Social services are supposed to have a duty of care not just for the offenders but all the safety of all the other kids on the streets too.

"If somebody commits a certain amount of offences and continues to re-offend then someone needs to step in.

"The red flags were there and they were ignored. Someone in the social work department wasn't doing their job.

"It's a total failure from the system, it's a failure to me and Kayden and our whole family. We've been completely let down."

During the trial, the court heard that Stewart and the 15-year-old - while acting with Turley - chased Kayden and repeatedly stabbed him with a lock knife after he fell to the ground.

Stewart brandished his baton and was heard to shout "Murray Boys".

He then told a witness at the scene that his victim "deserved it."

After running from the scene, Turley stuck the knife into the grass and was overheard boasting that he "just done him."

Turley also shouted "One-nil." CCTV showed the trio running down a road near the beach - stopping momentarily to embrace each other.

Passing sentence, Judge Lord Scott said Moy's death was "pointless and unnecessary".

He said the attackers "travelled to Irvine, armed, intent on a reprisal for some slight".

The judge added: "It could have been anyone but Kayden slipped and fell."

Moy believes the council should have done more to monitor his son's killers.

He added: "I truly believe this could have been prevented and I will do everything I can to make sure another family doesn't go through this.

"Nothing can bring Kayden back. I'm not looking for excuses, I'm looking for answers and to find the person who is also partially accountable for Kayden's death.

"All I want now is answers from this."

Weeks after the killers were jailed Jay Stewart posted a video online from jail in which he appeared to boast about stabbing Kayden.

The video, filmed in a cell in HMP Polmont and posted on Snapchat, showed Stewart topless, masked and rapping about the killing - claiming he will act violently again once he is released.

In August, Cole Turley - the only of the three to plead guilty to murder - lodged an appeal against his life sentence.

Meanwhile, the first minister said he was "incredibly grateful" to Kayden's parents for meeting him earlier this week.

Swinney added: "To lose a child in such horrific circumstances is unthinkable and Kayden's entire family continue to be in my thoughts as they show such immense strength in the face of this tragedy.

"The justice secretary and I listened carefully to the points Kayden's parents made, particularly around reoffending and the dangers of carrying a weapon.

"Where there are lessons to be learned and potential policy legislative changes that the government can make, we will consider those fully."

The first minister pledged to update Kayden's parents on all the points that were discussed and said he would be happy to meet them again.