A conspiracy theorist's laptop and mobile will be analysed at an inquest into his death after the UFO expert vomited two litres of black fluid and died aged 39.

Max Spiers's laptop was wiped when authorities returned it after his death more than two years ago during a trip to Poland to attend a conference.

Today a pre-inquest review at Guildhall in Sandwich, Kent, heard how the contents of his SIM card were also of particular interest.

Before he died Mr Spiers messaged his mother, Vanessa Bates, saying: 'You're boy's in trouble, if anything happens to me, investigate.'

An initial inquest opened in December 2016 when the court heard he vomited two litres of black blood, but the inquest was adjourned last year.

The father of two allegedly made many 'enemies' in his investigations. His inquest will now be held over four days from January 7, 2019.

Authorities in Poland, where Mr Spiers was attending a conference, initially concluded the sudden death was due to natural causes.

At the pre-inquest review today at the Guildhall in Sandwich, Kent, the court heard the barrister for Max's mother, Adam Taylor, call for members of the Polish emergency services to appear as witnesses at the inquest.

Sections from a 700-page docket of statements and evidence assembled will be translated from Polish for next year's inquest.

Possible evidence over whether disciplinary proceedings were brought against police officers in Poland over Mr Spiers's death should also be heard at the inquest, the court heard.

Mr Taylor said that Mr Spiers's laptop was wiped but that it was not empty at the time of his death.

He confirmed analysis of a laptop and a mobile phone that belonged to him should also be presented at the inquest.

'The way in which they were returned and what was done to them is clearly one of the big mysteries,' he said. 'The family has no knowledge whatsoever of what the results of that analysis were.

'The issue is the Sim card and what was on it. Without sight of the report the family has no answer to these questions.'

There were also a 'number of discrepancies' in emergency services accounts about Max's death, the court heard.

Monika Duvall, a friend who Mr Bates had reportedly been living with, was also asked to attend the inquest.

Speaking afterwards, Vanessa expressed concerns about being able to bring the Polish witnesses to the inquest.

'Today felt very positive. It's just over two years now. I did not expect him to go to Poland and not come back.

'We've got hundreds of pages we are working our way through which are all in Polish. It's been difficult but gradually we've worked our way through. There certainly was some mention of that from the Polish side.

'We've still got stuff that are not translated and I think when we get to the inquest we will know more about whether police procedures were or were not followed. He should be here. He was very fit and healthy when I said goodbye to him.

'Everything that we have in terms of health records before he went were that he was in great health. This was an enormous blow. I miss him dreadfully.'

After Mr Spiers's body was repatriated to the UK, doctors at a Margate hospital were unable to determine the cause of his death.

Kent Police then launched a joint investigation with Polish police into the conspiracy theorist's death.

At an inquest opening in Canterbury in December 2016, the court heard how the 39-year-old had been visiting Poland to speak at a conference after holidaying with a friend in Cyprus.

Shortly before his death, Mr Spiers was said to have been probing into the lives of well-known figures in politics, business and entertainment. At the time his mum Vanessa said she feared the worst.

'I think Max had been digging in some dark places and somebody wanted him dead.'

She is hopeful the investigation will shed light on the mysterious death.

'It's been a long time coming, but I'm just relieved that at last something is happening and there is a proper investigation and inquest,' she added.

Her theory was shared by many online, with other conspiracy theorists, UFO investigators and bloggers calling the circumstances of Mr Spiers' death suspicious.

At the time, Coroner Alan Blunsdon told the court he was still awaiting a report from Polish authorities, adding that the workload of Kent Police may delay forensic analysis of Mr Spiers' phone and computer.

Coroner Christopher Sutton Mattocks set the date of January 7 for the four-day inquest, which will be heard at the Archbishops Palace in Maidstone.

He said: 'It is extremely important that when we start everybody is completely ready for this and we have all the information available.'