The suspected UK fraudster is now accused of pretending to be an associate of Elon Musk to lure people to invest in Switzerland.
The extradition to the UK of fugitive Mark Acklom has been blocked because Swiss prosecutors have launched an investigation into new fraud allegations.
If the 45-year-old is charged and convicted in Switzerland, his British trial could be delayed for years.
UK extradition papers were served on the Swiss before this week's 40-day deadline after his arrest near Zurich on 30 June.
But six investors have given police statements alleging that together they lost about £750,000 invested in a company run by Acklom, who posed as a Spaniard named Manuel Conesa Escolar, and so his extradition is on hold.
The company Swiss Disks claimed to be developing a black box data recorder for driverless cars and used a glitzy website with dynamic videos to lure investors, promising huge profits.
Its website also showed images of luxury cars to imply it had the backing of major manufacturers.
According to investor Harald Herbon, a former banker, Acklom was a reclusive figure whose wife told suspicious neighbours he was "the right-hand man" of car technology pioneer Elon Musk and "the real brain" behind Tesla cars.
Mr Herbon said he became chief executive officer of Swiss Disks after investing 400,000 Swiss francs, roughly £400,000.
He never met Acklom, who would always make excuses to miss meetings, and dealt with him by phone only. He admits he should have been more careful.
Mr Herbon said: "He is brilliant in operating with people. He tells you a story and after a few minutes you believe him. The product idea was very good, but all we had to show for our investment was a prototype built in a little garage.
"He promised us billions and said Swiss Disks would be one of the biggest companies within a year. It made sense. He sent me a contract to sign showing that Elon Musk had invested five billion francs."
Acklom is currently in Champ-Dollon prison near Geneva awaiting the outcome of fraud investigations by prosecutors in three Swiss cantons.
The Swiss federal prosecutor's office said: "In the course of Swiss criminal proceedings, the person was handed over to the public prosecutor's office of Canton Geneva on 6 July 2018. The Swiss criminal proceedings has priority over the extradition proceedings."
Acklom, who allegedly also used the alias Marc Long, is wanted in the UK on 20 fraud charges after he allegedly stole the life savings of Carolyn Woods, a Gloucestershire woman he promised to marry in 2011.
Mr Herbon said: "A lot of people came forward with complaints to the police and now he is not going to Great Britain. He must pay the price in Switzerland for what he has done here. After that we can send him to the UK where he can get arrested again."
He rented Acklom a luxury lakeside apartment in Wadenswil, where Acklom was arrested in June. He said Acklom paid the first month's rent of 7,500 francs upfront, then promised to set future payments against his company profits.
Mr Herbon said he had started a process to register Swiss Disks as a bankrupt company and said he had no hopes of getting back his investment
The Crown Prosecution Service and Avon and Somerset Police, who investigated Acklom's involvement with Ms Woods, said they did not know what was happening with the extradition request.
Ms Woods told Sky News: "I'm disappointed at the extradition delay, but I'm glad Acklom is still in custody."