Detective Chief Inspector Gary Jubelin announced his resignation from the NSW Police Force amid allegations of misconduct. He was stood down from the Tyrrell case before State Coroner Harriet Grahame commenced a coronial inquest into the disappearance of the toddler in March.

Det Insp Jubelin is one of the country's most high-profile detectives having served 34 years on the force and leading investigations into major crimes including the murders of Mathew Leveseon and three Bowraville children.

He has been interviewed by the Professional Standards Command over his conduct on Strike Force Rosann, the unit he commanded in the search for William Tyrrell since the toddler's disappearance in 2014.

It is believed Det Insp Jubelin is facing allegations relating to staff management and using a mobile phone without a warrant to record someone.

He denies all wrongdoing and has continued to work at police headquarters since the internal inquiry began earlier this year.

A report from the internal misconduct investigation is yet to be made public.

Police Minister David Elliott said he had no concerns about the ongoing management of the Tyrrell investigation.

"I have the absolute confidence of the NSW Police Force to do a thorough investigation into any matter," he said.

Police Command has now put their "most senior homicide" investigator in charge - Detective Chief Inspector David Laidlaw.

More than 15,000 pieces of evidence have been collected by Strike Force Rosann which is made up of 30 of the best officers from across the state.

An inquest into the disappearance of William will continue in August.

Gary Jubelin is widely known on the Mid North Coast for his unfailing commitment to the families of the three children murdered in Bowraville nearly 30 years ago and his dogged determination to resolve the William Tyrrell case.

In a candid interview in 2016, with our journalist Ute Schulenberg, Gary Jubelin said he had never really thought about being a policeman until a 'light bulb' moment as a directionless 22-year-old working on a building site.

He saw police "chasing a bad guy through Ryde" and thought that looked like something he wouldn't mind doing.

He signed up the next day.

More than 30 years later, he's still "chasing bad guys" and still passionate about getting justice for the victims of crime.

Born in Paddington, Gary grew up in Epping with two sisters and a brother, and supportive parents, who were somewhat bemused at his choice of profession.

"I found that crooks and that side of life interested me," Gary said.

"Their strength of character, their spirit - I love being in the interview room.

"And there was certainly the excitement of the job - being paid to chase someone and tackle them."

From early in his career he had his eye on being a detective.

"You'd go to major crimes and set up the tape and then the detectives would come in ... they were the 'heavies' and clearly working at the sharp end of things," he said.

"But you had to be tapped on the shoulder for that, so I just kept my head down and worked hard."

When the invitation came, Gary never looked back.

"Homicide is the pinnacle for me - it's my passion," he said.

"These are the things I say to the young detectives who I work with and train. I want them to understand how hard you have to work and I want them to challenge me. I don't mind mistakes through effort but I don't like lazy police."

Gary's respect for those he helps is legendary, especially on the Mid North Coast, where he has supported the families of the three murdered Bowraville children (16-year-old Colleen Walker, four-year-old Evelyn Greenup and 16-year-old Clinton Speedy-Duroux) since he first walked onto the case in 1997.

"I had a young family myself at the time and was considering getting out of homicide but I was sent up there and spent the next 18 months working intensively on the case," he said.

"I thought I understood Aboriginal people but going there showed me a whole new world ... I don't like injustice. I couldn't believe the way the families had been treated and was shocked but understood the resentment the families had for the police."

The work does however come with many lows.

"Working homicide cases as long as I have exposes you to a lot of sadness, especially when speaking to people who have just had someone they love murdered," he said.

He cites a particular low point as the 2006 acquittal of a person for the murder of four-year-old Evelyn Greenup. It was the second acquittal of this person and a huge blow to the families.

"There was so much sadness and grief in the court but the families were so dignified," he said.

"Personally I felt like I had let them down after they had suffered so much ... it took a long time to get over that."

Currently the fact that Strike Force Rosann have not yet found out what happened to young William Tyrrell weighs heavily.

So how does Gary find some peace of mind in all this chaos and violence? How does his family cope?

Martial arts, qigong, meditation, a lot of yoga plus boxing are all in the mix, as are surfing and riding motor bikes.

"I'm into the yin yang of things ... meditation and qigong help give me perspective so I can check myself when things are getting stressful," he said.

"I throw myself into my work but I always make time for my fitness and meditation - it's how I balance myself."

Gary's personal life is no secret - it was writ large on the small screen in 2012 when the fifth season of Underbelly, Underbelly Badness, aired on Channel 9.

The series depicted the criminal activities of Australian kidnapper, murderer and drug-dealer Anthony Perish's (aka 'Rooster') criminal activities around the Sydney suburb of Lindfield and adjacent areas, and followed the NSW Police 'Strike Force Tuno', who finally apprehended him after almost a decade of intensive surveillance and informant information.

Gary led that team and his perseverance for all those years played no small part in the eventual success of the operation to convict five people for the abduction and murder of Terry Falconer.

Falconer's remains were found wrapped in plastic in the Hastings River, near Wauchope, in late 2001.

"I count it as a particular career high for myself and my team because we were consistently told we would not be able to solve it," Gary said.

The story is also documented in the book Bad by Michael Duffy, which is a "meticulous chronicle of an extraordinary police investigation into an Australian criminal empire that dwarfs all others".

Bringing all that to life on TV meant being followed around by writers for two years, and opening himself and his family to the world.

It also raised some tricky politics within the police force, where, in what can only be called 'true Australian fashion', tall poppies are not popular.

Gary laughs as he recalls initial discussions with screenwriters desperate to flesh out his character to add to the dramatic tension of the program.

"I told them I was divorced and had two children ... that I'd had a long term relationship with a fellow senior detective ... and at the time was in a relationship with an Aboriginal clinical psychologist from Perth, who I'd met on a murder trial," he said.

"They couldn't have been more pleased."

Pleased too were his two children: "They were teenagers at the time and it really gave me some street 'cred' with them.

"I felt happy with the series because it showed the effort police put into investigations, but it was also confronting seeing my life played out on screen."

Gary admits he can't imagine living a 'normal life', although there are times when a quieter existence looks attractive.

"I actually really like the pressure and I'd die of boredom doing anything else," he said.

"I've had such a varied career. Police work has opened so many doors for me - I worked in London on the Gordon Wood matter (Wood was convicted of the murder of model Caroline Byrne; the conviction was later overturned), I've been in Hong Kong, Shanghai, Beirut, Canada, Fiji, New Zealand and Paris as a result of my career.

"I've worked in Close Personal Protection, including with then prime minister John Howard for a few weeks, accompanying him on his morning walks.

"And when the Olympics were in Sydney I took care of Heads of State from Turkey and Bulgaria.

Gary says that in spite of being written off as a trouble-maker by many, he really is a loyal officer.

"I know I can polarise people because I fight for what I believe is right and I've never sold out," he said.

"But I truly believe it is a privilege to be a policeman and to investigate crimes.

"We are public servants and we are there to serve the public. There are a lot of good hardworking police who are dedicated and go about their business efficiently and remain unrecognised. I feel privileged to work with them."