The Ontario Provincial Police have been called in to investigate Ornge, the embattled air ambulance service under fire for misuse of public funds.

CTV Toronto's Paul Bliss reports that the Ministry of Health called police Thursday morning after discovering "financial irregularities" at the not-for-profit organization.

Ornge confirmed the OPP investigation on Thursday but said they could not offer further comment.

OPP acting inspector Cathy Bell told CP24 that investigators will take the time they need to complete a thorough investigation.

More than 40 forensic auditors have been combing through the books at Ornge since questions were raised about spending and helicopter purchases.

The Ontario government began investigating a number of companies set up by Ornge, which receives $150 million a year in provincial funding.

"We have been trying to get information from Ornge. I can tell you that I was and we were lied to by Ornge on aspects of their operation," Health Minister Deb Matthews told CTV News.

Police were called by the Ministry of Health over two financial transactions. In one case, Ornge loaned its former CEO Chris Mazza $1.2 million to purchase a home in Etobicoke, which is now up for sale. The company has placed a lien on the property to retrieve $500,000 dollars.

Government auditors have found no evidence Mazza paid interest on that loan.

Detectives will also probe a $6.7 million payment made by an Italian helicopter company immediately after Ornge bought 12 of its helicopters.

Former CEO Chris Mazza and COO Maria Renzella were formally removed from their positions on Feb. 2, and the board of governors was replaced.

Ontario's opposition parties went on the attack after the news broke Thursday, pointing the finger at the Liberal government and accusing them of mismanaging the agency.

"The very least this government should do is come clean with Ontarians," said Ontario NDP Leader Andrea Horwath. "Truly peel the orange and let us know exactly what's gone on there."

Conservative MPP Frank Klees demanded Health Minister Deb Matthews "step aside" during the police investigation, claiming there is no longer confidence in her leadership.

"I believe we are just starting this story," Klees told reporters. "Because of the lack of action on the part of the minister, we have no idea how many lives were put at risk as a result of the mismanagement of the people in this organization."