IT left scores of investors round the world fearing the worst when it collapsed this time last year.

Now detectives investigating York-based Challenor Property Developments are seeking help from the Spanish and American authorities.

Applications have been made to the Spanish and US High Commissions, seeking agreement for inquiries to be carried out on behalf of North Yorkshire Police in their countries.

And while detectives from Britain do not have jurisdiction to conduct inquiries abroad, officers might subsequently travel out to collect evidence.

Police said today a total of five people had now been arrested on suspicion of conspiracy to defraud and money laundering.

Detective Sergeant Garry Ridler, who is leading inquiries into the Poppleton-based organisation, said that while four people had been arrested in January, a fifth person had subsequently been arrested.

He said the five had recently answered police bail and had it extended until November, pending further inquiries.

He said police had now interviewed virtually all the 50-plus members of staff who had worked at Challenor, quite a few of whom had come forward after reading an appeal in The Press earlier this year. A total of 196 Challenor customers had now complained to police, some from as far as Russia.

He said there were three key strands to the investigation:

* Allegations of mortgage fraud.

* The alleged theft of clients’ money.

* Complaints about a franchising operation.

He hoped the investigation would be concluded by early next year, adding: “It’s a massively complex inquiry.”

The Press exclusively revealed this time last year how Challenor’s offices at Regency House, Westminster Business Park, in York, had suddenly closed down, leaving scores of property investors fearing they had lost thousands of pounds.

Dozens of worried investors contacted The Press to say they believed they might have lost between £5,000 and £50,000 in deposits on properties, franchises and Challenor “membership” payments.

Some people said they feared losing their entire life savings.

The Press reported earlier this year that it understood the four arrested included Challoner boss Chris Douglas and his wife, Karen, of Fulford, and a large amount of property and documents had been seized during searches of several properties. Police warned then that more arrests would be made as the long investigation continued.

Mr Douglas apologised last summer for Challenor’s demise, which he blamed on interest rate rises, buy-to-let lending institutions which withdrew products from the market and “non-payers and trade debtors”.