Last week the man responsible for the shocking murder of Sunday school teacher Gill Montgomery was sent to Broadmoor following an unrelated brutal attack.

The sentence marks the end of a case which saw Sussex Police track the suspect to Turkey, where he was convicted of the murder, only to be released after serving a fraction of the sentence.

Here Chief Superintendent Dick Barton talks to Jessica Mangold about his role in the hunt for the killer and the questions still unanswered.

When Hakan Yagiz was sentenced to an indefinite stay in Britain's most notorious secure unit, a lone policeman sat at the back of Lewes Crown Court, meticulously taking down each word.

As divisional commander for Hastings and Rother, it is not routine for Chief Superintendent Dick Barton to spend his mornings following court cases.

But this single hearing signalled the finish of a complicated case which the officer had begun to follow when he was still a Sussex Police detective chief inspector in the late Nineties.

Mr Barton said: "I first became familiar with the case when it was handed to me as a review. Yagiz was a suspect, we knew he was in Turkey, but there were still loads of question marks.

"While my mind is always open on any inquiry, what struck me most in this case was the clear evidence this guy was the murderer."

Former nurse Gill Montgomery was found dead in her flat in Cloudesley Road, St Leonards, in April 1995.

The divorced mother, 53, who was known throughout the community for her voluntary work, had died from a single stab wound to the neck.

Police later revealed whoever had got into her flat had escaped with less than £100 and a reward of £10,000 was put up for information leading to an arrest.

Despite a tip-off naming Yagiz in the weeks after the murder, the former hairdresser escaped arrest after fleeing the country to join the Turkish army.

In 1997, Mr Barton was ordered to track down Yagiz and bring him to court.

But even with the support of Home Office ministers and a wealth of evidence and statements, Turkish authorities refused to hand over the suspect.

Realising Yagiz was going to go to court outside the UK, Mr Barton set about preparing evidence for judges in Turkey.

He said: "One of the difficulties I had was trying to get my head round the difference in the law between the two countries and the difference in culture.

"What you have here is a judge asking very specific questions but the things we wanted to expand on in this case the Turkish authorities were not interested in."

It was another two years before Gill Montgomery's family would see Yagiz stand trial in Turkey.

Mr Barton travelled to the hearing, arriving with the Montgomery family to discover a justice system completely unlike anything he had experienced in the UK.

He said: "The Turkish court was in the middle of nowhere and the conditions inside were fairly medieval.

"In the court room we were within yards of Yagiz and that was very traumatic for the family.

"There were armed military personnel who sat around, leaving their guns on the ground and people up for murder charges were roaming around the court precinct."

"I was getting increasingly frustrated about not being able to understand what was being said.

"When the verdict was read out we could not understand it but there was a quick interpretation and Gill's sister and niece were both crying but they were relieved."

The Turkish court found Yagiz guilty of murder and sentenced him to 36 years in prison with hard labour.

But in March last year, Mr Barton received the devastating news that Yagiz had walked free just one year into his sentence, returning to the UK thanks to a mass release of prisoners by the Turkish government.

He said: "We received no official notice. The first we knew of it was through police intelligence and because of the conviction in Turkey, Yagiz could not be re-tried for the offence in the UK.

Yagiz had been living with his family in Hastings for a matter of months, when worrying reports began to emerge about his behaviour.

Sent for a brief spell to a medium-secure unit in Surrey, Yagiz attacked another patient and was arrested and sent to Lewes Prison on remand.

There he attacked his cell-mate in a row about bunk beds last December, fracturing his victim's jaw and kicking out four of the man's front teeth.

Giving evidence at Lewes Crown Court before Yagiz was sentenced for the latest attack, doctors from Broadmoor spoke about worrying displays of schizophrenia, violent episodes against his family and hallucinations.

Mr Barton said: "I always had a fear this man who had committed murder was in our community and it is a question of what we could do next to ensure public safety.

"But this case will never be closed for me while there are still question marks and one of my deepest frustrations is that we have never pieced together the whole story about what happened to Gill the day she was murdered."