A musician who brutally murdered a teenage girl he snatched from a Plymouth bus stop has been warned by a judge he may never be free again.

Cody Ackland, a car valet and aspiring rock star, had developed an obsession with serial killers, in particular US murderer Ted Bundy, in the months before he killed 18-year-old Bobbi-Anne McLeod.

Ackland, 24, who was a guitarist with local indie band Rakuda, was unknown to the police when he bludgeoned Miss McLeod with a claw hammer in a “prolonged, savage and merciless attack”.

Miss McLeod had been waiting for a bus at around 6pm on November 20 last year when Ackland struck her twice with a hammer.

He then loaded the semi-conscious teenager into the footwell of his Ford Fiesta and drove her 20 miles to the Bellever Forest car park on Dartmoor.

In his confession to police, he claimed Ms McLeod could still walk, although he had to support her, when they arrived and had told him “I’m scared”.

He claimed he had replied: “So am I, I have never done this before”.

Ackland then struck her 12 times to the head and face with the hammer, before standing on her neck when he saw she was still breathing.

Ackland burnt her handbag and loaded her blooded body into his boot and drove 30 miles back towards Plymouth to Bovisand where he stripped her naked and left her in undergrowth.

He later threw away her clothes in an allotment before spending the next 48 hours socialising with friends.

Three days later, Ackland turned himself in and confessed, telling detectives where he had dumped her body.

At a previous hearing, Ackland, of Radcliffe Close, Southway, Plymouth, pleaded guilty to murder.

On Thursday, he was handed a life sentence and ordered to spend at least 31 years in prison.

In a victim impact statement, Miss McLeod’s family said: “Our lives have changed forever. We have not been able to say goodbye to Bobbi-Anne and we can only imagine the things he did to her – the thoughts are continually going around in our minds.

“Why Bobbi-Anne? Why make her suffer? To know her final hours were spent being tortured destroys us inside.”

Ackland kept more than 3,000 grisly images on his phone, depicting dismembered or dead bodies, post-mortem examinations and murder scenes, the court heard, and read extensively about serial killers – in particular 1970s US murderer Ted Bundy.

He told a psychiatrist that he had been feeling low on the day of the murder, but afterwards he had “not felt the same feelings of depression and resentment as before”.

The psychiatrist remarked it was as if “this violent act has somehow rid him of these feelings”, and warned this risk was unlikely to go away.

Judge Robert Linford told Ackland: “On November 20 last year you subjected Bobbi-Anne McLeod to a prolonged, savage and merciless attack.”

He continued: “She was a young, popular and much-loved person, you caused outrage and fear in this part of the country and with good reason, it was utterly motiveless.”

Judge Lindford told Ackland that he would remain indefinitely a “highly dangerous person”, adding: “There is a strong possibility you may never be released from prison.”

(Ackland) describes it as self-medicating, if he can shock himself he might shock himself out of what he felt he had become capable of doing

Ackland’s barrister Ray Tully QC recounted Akland’s struggles with ADHD, depression, dyslexia and anxiety growing up, and said that he was overwhelmed with feelings of self-loathing.

Mr Tully said his client’s obsession with images of murder victims had to be viewed through the “prism” of his mental health struggles.

“Psychiatrists characterise it as a kind of self-harm, someone who has developed an addiction to seeking out material, going back to it again and again,” he said.

“(Ackland) describes it as self-medicating, if he can shock himself he might shock himself out of what he felt he had become capable of doing.

Mr Tully said although Ackland had searched online for remote locations on Dartmoor and for hammers, crowbars and cutting tools in the days before the murder, the attack on Ms McLeod was not premeditated.

Judge Linford said: “I am satisfied so that I am sure, based upon all the material I have read, that you were planning to kill.

“I cannot be satisfied to the required standard that as you drove to Plymouth on the evening of November 20 you had a settled intention to kill that night, but it was only going to be a matter of time.”

The day after the murder Ackland threw the hammer into the River Tamar and a carrier bag containing his and Ms McLeod’s blood-stained clothing into nearby allotments.

Later, he carried on as normal, going for pizza with a friend, attended band practice, got a takeaway and drank into the early hours at a pub lock-in.

Friends recalled the usually somewhat reserved Ackland as being “happier than usual”.

Ackland looked at the judge throughout his remarks and nodded as his sentence was passed.

As he left the dock, Miss McLeod’s brother Lee shouted: “You’re a dead man.”

Miss McLeod’s mother Donna wept throughout the hearing.