There’s been no shortage of white-collar prosecutions gone awry in recent years. But we doubt that’s much consolation for federal prosecutors in Boston, whose criminal cases against a quartet of former Stryker Biotech officials abruptly imploded over the last three weeks.

At a status conference on Thursday, prosecutors voluntarily dismissed fraud charges against Mark Philip, who was president of the medical device company until 2008. The move came just after Philip’s lawyers at Edwards Wildman Palmer showed prosecutors new evidence.

“Earlier today, the government had an opportunity to review some documents that had previously been withheld as privileged,” assistant U.S. attorney Jeremy Sternberg told Boston federal district court judge George O’Toole, Jr. on Thursday, according to Bloomberg. “After reviewing the documents, it’s the government’s plan to file a motion to dismiss in the case against Mr. Philip.”

The dismissal caps a rollercoaster prosecution for the U.S. Attorney’s Office in Boston, which specializes in health care fraud. In late 2008 and early 2009, it secured guilty pleas from a Stryker Biotech regional manager and three sales representatives. In October 2009, prosecutors turned up the heat and indicted Philip and three other Stryker employees on conspiracy and wire fraud chfarges. The indictment alleged that they misled doctors about off-label uses for their bone-healing products and lied to the U.S. Food and Drug Administration. Judge O’Toole severed Philip from the case on attorney-client privilege grounds in January, setting the stage for a trial against the three other employees–managers David Ard, Jeff Whitaker, and William Heppner.

Shortly after opening arguments in that trial, the DOJ dropped all charges against Ard on Jan. 17 at the request of his lawyers at Wilmer Cutler Pickering Hale and Dorr. Two days later, the DOJ dropped charges against Whitaker (represented by Nutter McClennen & Fish) and Heppner (represented by the boutique LibbyHoopes). On Jan. 18, Stryker Biotech agreed to plead guilty to a misdemeanor charge and pay a $15 million fine.

Stryker’s lawyer, Brien O’Connor of Ropes & Gray, told us last month that that government investigators never actually spoke to the seven surgeons identified in the indictment as victims of the alleged fraud. But the defense did, and O’Connor promised the jury in his opening that the doctors would testify at trial that “the defendants did not lie to them; the defendants did not deceive them; the defendants did not defraud them in any way.”

And the mysterious documents that sank the government’s case against Philip on Thursday? Edwards Wildman partner Stephen Huggard wouldn’t to go into details, but he told us the documents showed that Philip, who faced a maximum 20-year sentence, acted in good faith. “When there were decisions to be made, Mark engaged in discussions with counsel, his compliance department, and his regulatory department. And we were able to show the government through selective presentation of documents that that’s what happened,” Huggard said.

In a statement, U.S. Attorney for Massachusetts Carmen Ortiz chalked the dismissals up to “unfavorable pretrial rulings, combined with a strategic error in preparing for trial.”

“At the end of the day, doing justice meant dismissing the charges, rather than subjecting these individuals to a protracted trial where the government could not put its most effective case before the jury,” Ortiz added.

It became “plainly obvious” at the close of opening arguments last month that the case should not have been brought, said Brent Gurney, a WilmerHale partner in Washington D.C. who represented Ard. “We made it clear that we intended to call a number of doctors who would testify that they were never defrauded. And we planned to call [Stryker] witnesses who would testify that it made no sense that they would lie to doctors because their business model relied on strong and trusting relationships with these doctors.”

“I give [the DOJ] credit for recognizing that bringing this case was a mistake, but they did it at the eleventh hour,” said Gurney. “The lesson here is do your homework.”