A federal appeals court has overturned a judge’s unusual decision to acquit a Maryland doctor whom a jury found guilty in a $15 million health care fraud case involving COVID-19 tests, but upheld a ruling to grant him a new trial.

Dr. Ron Elfenbein was convicted in 2023 in U.S. District Court in Baltimore of five counts of health care fraud. Federal prosecutors alleged that Elfenbein, 51, billed Medicare too much for visits that only lasted a few minutes and submitted records detailing medical services that his clinic did not provide.

Elfenbein owned Drs ERgent Care LLC, which did business as First Call Medical Center and Chesapeake ERgent Care in Anne Arundel and Prince George’s counties. He also ran an urgent care center at Baltimore-Washington International Thurgood Marshall Airport that tested people for the coronavirus.

The charges stemmed from five patient visits that took place between March 5 and May 12, 2021.

But U.S. Senior District Judge James K. Bredar acquitted Elfenbein more than four months after the trial, writing in a 90-page opinion that the government did not present enough evidence to prove the charges beyond a reasonable doubt.

“In this context, it is not a criminal offense to take advantage of loose definitions or an explicit loophole any more than is it to do so when citizens prepare their tax returns,” Bredar said. “Citizens, including healthcare providers, cannot be held to criminal account for doing only what a technical regulation is reasonably read to permit, even if to do so would seem to benefit them excessively.”

A three-judge panel of the U.S. Court of Appeals for the 4th Circuit disagreed.

In a 31-page opinion on Thursday, Circuit Judge Julius N. Richardson wrote that the jury had enough evidence to convict Elfenbein, though the case was thin.

“Sometimes, the difference between conviction and acquittal comes to whether the jury believes a single witness,” Richardson said. “It is not for us to second-guess the jury’s belief.”

“Or, closer to this case, the jury’s decision may rest on how it interprets cryptic testimony,” he added. “That, too, is the jury’s job — not ours.”

At the same time, Bredar was owed deference regarding his decision to order a new trial, Richardson said.

Neither Elfenbein nor his attorney, Martin Himeles Jr., could immediately be reached on Monday for comment.

Elfenbein’s medical license is active, according to the Maryland Board of Physicians. He lived in Arnold at the time.

When a grand jury returned the indictment in 2022, then-U.S. Attorney Erek Barron said Elfenbein “took advantage of a national health crisis to line his own pockets.”

“Our office has and will continue to investigate and prosecute fraud by anyone who used the COVID-19 pandemic to defraud individuals or the government,” Barron said in a statement.

A spokesperson for the U.S. Attorney’s Office, Kevin Nash, declined to comment.

It’s unclear if prosecutors will move forward with a new trial.