The first salvo in multiple investigations of the global pharmaceutical company Valeant was fired by federal prosecutors Thursday, who charged that a Valeant executive had colluded with the head of a Hatboro-based mail-order specialty pharmacy firm on a deal that cheated shareholders out of $300 million.

The criminal complaint, unveiled by the U.S. Attorney's Office in Manhattan, charges that former Valeant executive Gary Tanner received $10 million in kickbacks from Andrew Davenport, then-CEO of Philidor Rx Services LLC of Hatboro. Tanner had been instrumental in persuading other Valeant executives to purchase Philidor while failing to disclose his interest in the transaction, federal prosecutors said.

"Tanner was a senior executive at Valeant. As such he owed all of his duties to Valeant and its shareholders," said Preet Bharara, the U.S. attorney in Manhattan. "In violation of those duties, however, Tanner secretly agreed with Davenport to puff up Philidor's business" and promote its sale to Valeant.

Tanner, 39, of Gilbert, Ariz., near Phoenix, and Davenport, 48, of Haverford, were arrested Thursday on charges of wire fraud, money laundering, and conspiracy, and faced court appearances.

Little more than a year ago, Valeant -- based in Canada but with headquarters in Bridgewater, N.J. --  was one of the drug industry's hottest companies, its soaring stock price fueled by an ample drug pipeline and a strategy of aggressive price hikes. But its reputation began to tarnish after its secret relationship with Philidor was disclosed and multiple federal agencies probed allegations that the company employed clandestine tactics to substitute expensive brand-name drugs for cheaper generics recommended by physicians.

Since then, Valeant's stock has lost about 90 percent of its value. At the close of trading Thursday, shares in Valeant rose 12 cents to $17.98 on the New York Stock Exchange.

Philidor, which went out of business earlier this year, focused its business on filling specialty prescriptions and on an "alternative fulfillment" program that assisted patients in obtaining insurance-company sign-off on the use of more expensive brand-name drugs in the place of generics.

According to the criminal complaint, Tanner and Davenport conspired to steer Valeant executives toward purchasing Philidor. Davenport was a 36.5 percent owner of Philidor, according to the complaint, and Tanner had a secret arrangement with him in which he would direct Valeant resources toward Philidor in an effort to make it a more attractive acquisition target.

Once the purchase was concluded, Davenport reaped $40 million, kicking some of that back to Tanner as well as buying stocks, luxury goods, and a $50,000 wine cellar, the criminal complaint says. In one email from Davenport to Tanner, Davenport compared their activities to the western Butch Cassidy and the Sundance Kid and remarked that the two would "ride into the sunset."

In an effort to ensure that the acquisition went through, Tanner worked to discourage Valeant from working with other companies that provided services similar to Philidor's, and he arranged for Valeant sales staff to assist in marketing Philidor's medications.

Although Philidor was ostensibly a separate company, Valeant was instrumental in its founding in 2013 by providing financing personnel and supervision, according to the complaint. Like other major drugmakers, Valeant had concluded that it needed assistance in marketing and filling specialty pharmaceutical prescriptions and believed initially that Philidor would meet that need.

Tanner, who was a senior Valeant executive and was paid millions in salary, bonuses, and stock options by Valeant, owed his allegiance to his employer  and had signed a company conflict-of-interest policy that barred him from engaging in transactions that would be harmful to Valeant, including transactions with customers. He also was required to make a full disclosure of any outside activities that might pose a conflict of interest, although he never did, according to the criminal complaint.

Eventually, Valeant entered into an option agreement with Philidor in 2014, agreeing to an up-front payment of $100 million and additional payments of more than $100 million provided the company met certain performance milestones. Valeant also agreed to forgive financing it provided Philidor for purchases of Valeant drugs. The total loss to shareholders in the transaction approached $300 million, according to the complaint.

Tanner and Davenport set up shell companies to launder the kickback payments.

In a statement, Howard Shapiro, an attorney representing Tanner, said his client would be shown at trial to be innocent of the charges. "It was Gary Tanner's job at Valeant to grow and promote Philidor. He performed that job exceptionally well, greatly benefiting Valeant's shareholders, and regularly communicated to his superiors what he was doing," Shapiro said.

Davenport's attorney did not immediately respond to phone and email messages from the Associated Press.

This article contains material from AP.