Daniel Morcombe’s killer has been locked up until 2031 but there are concerns it won’t be long enough to protect the public from the serial child molester.

Daniel Morcombe’s killer will be in his 60s before he can be released from jail, but whether that’s enough to protect the public is under scrutiny.

Brett Peter Cowan was on Friday given life imprisonment with no parole for 20 years for murdering the Sunshine Coast schoolboy in 2003, but Queensland’s attorney-general has raised the possibility of appealing the sentence.

Jarrod Bleijie says he is reviewing the penalty and receiving advice from the Director of Public Prosecutions.

The trial judge herself raised questions about Cowan’s prospects of rehabilitation with a warning for those who would consider releasing him when he becomes eligible for parole in 2031.

“Whenever anyone is considering the prospect of granting you parole in the future they should mark my words that you are a convincing, plausible and adaptable liar, and prepared to lie to advance your own interests,” Supreme Court Justice Roslyn Atkinson told the serial sex offender on Friday.

Justice Atkinson was required to sentence Cowan to a non-parole period of at least 15 years, but felt the enormity of Cowan’s crimes and his history warranted a harsher penalty.

The judge had barked at father of three Cowan, 44, to stand up in the Brisbane Supreme Court dock to hear her forceful sentencing remarks, which ran for more than 20 minutes.

“Everything about what you did to that child was horrific and disgraceful,” she told the prisoner, who stared straight ahead with his hands folded in front of him.

“This is not just a murder but a terrible murder. It has had widespread and shocking impacts.”

Daniel’s parents Denise and Bruce Morcombe, now child safety campaigners, were not in court, choosing to attend a fundraiser instead.

They had endured an emotional day on Thursday when Cowan, who has already spent two-and-a-half years behind bars, was found guilty of indecently treating and murdering Daniel and interfering with his corpse.

Powerful victim impact statements from the couple and their two sons read in court described how the “evil” Cowan had torn their family apart and left them with unbearable images of what had happened to their son.

Daniel was 13 when he vanished while waiting for a bus at Woombye on the Sunshine Coast on December 7, 2003.

Cowan was arrested in August 2011 following an undercover police sting, and Daniel’s remains were discovered in bushland in the Sunshine Coast hinterland later the same month.

The former tow truck driver has previously been jailed for sex crimes against young boys in Brisbane and Darwin in 1987 and 1993, but had history of molesting children dating back to his teen years.

Brisbane Lord Mayor Graham Quirk said Brisbane’s Story Bridge will be lit red on Friday night in honour of the Daniel Morcombe Foundation, the charity set up by Daniel’s parents.

Daniel was wearing a red T-shirt when he was abducted.