It is the case that has left police baffled – how could a popular student walking home from a night out with a tracking device vanish into thin air?

Jack O’Sullivan made sure he had his Apple AirTag on him when he set out to a party with friends six months ago, and that he explained how it worked to his concerned mother.

But when he failed to come home, it sparked a huge search that has still not born fruit half a year on.

His bizarre disappearance has left many scratching their heads – and raised fresh questions over police competence and how effective modern tracking technology really is.

Much like the cases of Jay Slater and Nicola Bulley before it, the mystery has caught the eye of TikTok mediums and amateur sleuths, many of whom have tormented his family with hoax calls and demands for money.

With police seemingly reaching a hurdle over the encrypted AirTag data, Jack’s mother, Catherine, has taken matters into her own hands and goes out every single day to search Bristol with the help of kind volunteers.

Mrs O’Sullivan has been praised for ‘adopting the role of Chief Inspector, Chief Constable and Detective Superintendent all rolled into one’ but concerned people have slammed the force and said it ‘beggars belief’ she feels the need to do so.

Avon and Somerset Police have been slammed by Jack’s family and the local community for not doing enough to find the 23-year-old.  

Mrs O’Sullivan, 52, told Sky: ‘Initially we were in the hands of the police and just were very accepting that everything we were told was being done was actually being done.

‘It’s just that as time’s gone on, we realise that things have been missed and not done as thoroughly as we thought they were.’

A post on the Find Jack Facebook page read: ‘The fact that Jack’s mother, and family, have been forced to adopt the role of Chief Inspector/Chief Constable/Detective Superintendent all rolled into one beggars belief. 

‘Arranging with landowners to access their property for clues, trying to gain access to drains etc. At a time when the mental load must be so overbearing for her, imagine having to try and orchestrate all of these leads for your own son.

‘Catherine O’Sullivan you are the very definition of a true mother, leader of the pack, and the whole of Bristol and the UK support you every step of the way. You incredible woman.’

She replied: ‘Thank you – Your words as so kind but unfortunately so true! We are really doing everything we can but at times it feels impossible.

‘I really don’t want to be an incredible woman – I just want to be Jack’s mum. Please god help us find my boy!’

Others slammed the force, with one commenting: ‘Shame on Avon and Somerset Police. Pull your finger out and do something to help find Jack.’

Some called it ‘shocking’ and blasted it as ‘injustice’ that more hasn’t been done to help.

On top of that, those on the Facebook group slammed amateur sleuths who have been spamming the page.

A post read: ‘Can I just say that speculation in this group isn’t helping anybody, let alone Jack’s loved ones.

‘This group is to try and help find Jack, not play detective. They already have one of those. Yes we already know the police have been shocking but it’s happened and we are where we are.

‘Stop with ‘I think this happened’ posts and just think how you would feel if you were the parent reading these comments on a regular basis.

‘I know many people think it’s helping but it really isn’t. This is stressful enough for family and friends without certain people making it worse.’

An admin replied to thank the user and said: ‘The last week has been challenging.’

Another person added: ‘The trend in recent years playing at armchair detectives in missing people cases like it’s a game, with no thought to the real people involved is disgraceful.’

Yesterday, an admin posted on the group warning of fake GoFundMe pages.

‘Please please please do not part with any money – this one says the deadline is 22nd Sept – which is total rubbish.

‘There is an official GoFundMe but we aren’t pushing it at the moment, people have been incredibly generous and we think we have enough for what we need to pay for right now.’

The family have also received appalling messages saying Jack ‘is being held and asking for ransom amounts for him’ as trolls try to cash in.

His mother added she has ‘lost all faith’ in Avon and Somerset Police’s investigation into Jack’s disappearance and goes out to search ‘daily’ – even hiring a private investigator.

She told the BBC: ‘I have had messages suggesting that Jack is being held and asking for ransom amounts for him.

‘People telling me that awful things have happened to him and where I might find him.

‘But what would anybody do in my situation? I have to read them, as bad as I know it is, putting myself through hell at times, but I can’t ignore anything.’ 

She posted on Facebook: ‘I have been contacted by mediums telling me Jack has been held hostage, murdered and giving me locations all over Bristol to go and look for him. I have had requests for payment so he can be released!

I have shared this type of information with the police but not had any response. They just ignore us!’

The amateur sleuths, fake GoFundMe pages and trolls distressing the family is disturbingly reminiscent of the behaviour of the public during Jay Slater’s disappearance in Tenerife.

While many people sent love and support, others posted conspiracy theories and threatened his friends and family.

Mrs O’Sullivan previously spoke out about the missing teenager to say it ‘brought everything back’ and said she sympathised with Jay’s mother.

It comes as questions grow over Jack’s Apple AirTag data. ‘I said to the police, Jack’s keys have got an AirTag. And I really thought that was going to be a really positive location finder,’ Mrs O’Sullivan told MailOnline.

Jack’s family are hoping more answers could lie in the phone and AirTag data. They say they don’t believe Avon and Somerset Police have fully analysed it because of being consistently ‘let down’ by the investigating force.

The family were initially told by police that Apple privacy laws would not allow them to pursue any of the AirTag data.

The O’Sullivan family went back to the police again, who this time indicated they had accessed the data. They were, however, told by officers that they thought ‘the battery must be flat on the AirTag because it’s not providing information’.

Jack’s mother explained: ‘We said, well it wasn’t flat when he’d left the house, because he demonstrated how it worked to me at 6pm that night.

‘The police then changed the story again and said, ‘Well actually we don’t think it was set up correctly, it was never registered’.

‘We were going around on this ridiculous circle of not getting anywhere.’

Mrs O’Sullivan said that the police’s latest statement two weeks ago was that the AirTag had been ‘registered to Jack’s ex-girlfriend’s account’ which is why they couldn’t locate it.

‘But I actually contacted her this weekend just to verify that and she said, ‘No that’s not true, I didn’t register it’,’ she revealed. ‘So we just can’t get a straight answer.’

Jack left the house party in the early hours of the morning of March 2 and mobile data shows that his phone was still in use at 6.44am – hours after he was last seen on CCTV.

The last confirmed sighting of Jack is at 3.13am as he walks onto a grassy area at the junction of Brunel Lock Way and Brunel Way, Bristol.

But while Catherine was forced to trawl through CCTV herself, she spotted a person – who she is adamant is her son – walking over Plimsol Bridge at around 3.25am, heading back in the direction of Bristol city centre.

When police were alerted to this, they later uncovered a second clip showing someone walking along the Bennett Way slip road at around 3.38am.

Jack attempted to call a friend who was still at the party at 3.24am. When the friend called back 10 minutes later, Jack answered but only said ‘hello’ before the call cut off.

His phone remained active on Find My Friends until 6.44am and Catherine could hear the phone ringing through when she was calling him, indicating the device was still working.

She said: ‘We’re desperately trying to get hold of the phone data that they [the police] tell us they’ve analysed. And they tell us ‘we have already told you the findings’. Well we would like to be certain of that, because they did the same with the CCTV.

‘They said they were certain of their findings, and they totally missed Jack on it.

‘So from our perspective, we can’t trust what we’re being told so we would rather have things ourselves and pay somebody to analyse it, and then we can then feel certain that it’s done.

‘If it hasn’t shown information, it hasn’t shown information. But we we can’t trust their processes because of what’s gone before.

‘What we do know is what the police have told us is that between when a call was made, we know when a call was received, and we know there are other chunks of data usage on that phone up until 5.40am.

‘And we know the phone was on the network until 6.44am. I’m not technical, so I don’t fully understand. But I’ve been told that the phone will ping off different masts and then you can kind of triangulate the location from it.

‘And we want to see if we can try and plot a route or the last time that phone worked. If we can be a little bit more specific with the area then that’s got to help in some way.’

One of the latest updates is that the family have managed to get a replacement SIM card because Catherine is the account holder of Jack’s phone so it is in her name.

The police said that they did not feel it was necessary, so the family have paid for it to be looked at by a cyber security company in Manchester.

The experts have had the SIM for two or three months and are trying to see if any of the apps had any form of location trackers on them, but it hasn’t provided answers yet.

Avon and Somerset Police say that since Jack’s disappearance, more than 20 different teams and departments have been involved in the investigation.

They have been supported by other agencies and emergency services, such as the fire and ambulance service, National Police Air Service, and RNLI.

A spokesperson said more than 100 hours of CCTV have been reviewed, 200 hours of searches on the river and the surrounding banks, mounted police searches from Bristol city centre to Flax Bourton, 40 land searches, and 16 drone deployments.

The force said it has received almost 100 calls from the public with possible sightings, and eight media appeals have been issued.

Assistant Chief Constable Joanne Hall said: ‘Our staff and officers remain committed to doing everything we can to find Jack and we do not underestimate what a distressing time this has been, and continues to be, for his family.

‘When I look at missing persons investigations [in Avon and Somerset] over the last year, we’ve had around 5 and a half thousand.

‘Missing people are somebody’s loved ones, they’re somebody’s family, and we don’t close the door on that.’

The force renewed its appeal for witnesses and said they will update Jack’s family when their handling of the complaint is finalised.

MailOnline has contacted the force for further comment.