An investigation has been launched into the financial affairs of a treatment centre for injured and ill police officers.

Detectives were called in after an internal inquiry at the Northern Police Convalescent Home uncovered evidence of possible criminal offences.

The charity-run home, in Harrogate, North Yorkshire, suspended its chief executive Alan Outhwaite two weeks before he was due to retire after 20 years in the role.

His secretary, who is his daughter but has not been named, has also been suspended while the investigation is carried out.

A detective from Durham Constabulary's economic crime unit has been appointed to conduct the inquiry, partly because Mr Outhwaite is a former North Yorkshire Police officer and being investigated by ex-colleagues would have proved difficult.

The internal inquiry is thought to have started after staff raised concerns with a new chief executive, Katherine Martin, when she took up her post a month ago.

A statement from the board of trustees of Northern Police Charities and Northern Police Convalescent Homes said: "The chairman and and executive of the board of trustees have conducted a management inquiry into issues that have been raised concerning several matters of the charities' business.

"An interim report has been received and as a consequence several matters of alleged financial irregularity have been referred to the police for criminal investigation.

"The former chief executive retired at the end of June 2004. The new chief executive Katherine Martin is providing the fullest co-operation to assist and inform the trustees' inquiries.

"It is not possible to assess the values involved but sums of £100,000 are speculative at this stage.

"The alleged irregularities do not concern any single donation, gift or subscription.

"The Charity Commission have been made aware of these inquiries and a briefing report for their consideration is being prepared by the chairman of the trustees."

Mr Outhwaite, who is believed to be on holiday in Australia, could not be contacted last night.

The statement from the trustees added: "The standard of patient care has never been in question or doubt and remains high and unaffected by any of the issues being enquired into by the trustees.

"It would now be entirely inappropriate for any further comment to be made either in regard to the allegations themselves or individuals concerned until Durham Constabulary have completed their inquiries."