In a highly unusual decision Monday, U.S. District Judge John Tunheim overturned the March jury conviction of a 40-year-old man from the Red Lake Indian Reservation who was found guilty of seriously injuring his 10-month-old son.

Tunheim, in a 40-page decision, said the prosecution had failed to prove its case and ordered James White Jr. immediately released from the Sherburne County jail.

White has been jailed since last September and faced a mandatory sentence of at least 10 years in prison.

Assistant U.S. Attorney Deidre Aanstad filed a motion asking Tunheim to delay White’s release for 30 days while the government decides whether to appeal his decision to the Eighth U.S. Circuit Court of Appeals.

Joseph Daly, emeritus professor of law at Hamline University, said that while it is quite common for attorneys to ask a judge to toss a guilty verdict, it is “very, very rare” for a judge to do so. “They leave it up to the jury,” he said.

Peter Wold, a well-known criminal defense attorney who was appointed by the Federal Public Defender’s office to represent White, said he’d tried about 125 cases in court, and this was the first time a judge had overturned a jury verdict.

Nonetheless, Wold said, “It is exactly what should happen. Everyone but that jury in the courtroom was stunned when they read the verdict. It wasn’t close to reasonable doubt. The alternate juror in the case came up and told us he didn’t know what happened,”

Tunheim wrote he was “extremely hesitant” to overturn. “However, in this case, justice requires an acquittal. A conviction must be supported by evidence beyond a reasonable doubt. Here, the evidence is simply insufficient.”

Wold’s partner, attorney Aaron Morrison went to the jail to tell White. “He had nothing but respectful things to say about the prosecutor and the judge and the system.”

The alleged victim, identified only by the initials A.W., was airlifted from a hospital on the reservation to a larger hospital in Fargo, N.D., last August.

Several days later, White was arrested and ultimately indicted on a charge of assault resulting in serious bodily injury.

White’s mother, Cheryl Maxwell, testified that she returned home on Aug. 30, 2013, to find that A.W. appeared to be choking from eating rice soup she made earlier. White was holding the boy, doing CPR, and told her to call 911.

A doctor for the prosecution testified the boy had acute bleeding near the brain, which could have been caused by head trauma which he thought was “nonaccidental.”

The doctor said on cross examination that he “can’t pinpoint exactly what happened or how it happened.”

While there was no evidence of prior abuse by White or Maxwell, Maxwell’s 8-year-old son from a previous relationship had a history of injuring A.W., Tunheim wrote.

Tunheim said the prosecution relied on circumstantial factors that were “too weak, even in their totality, to support a finding of guilt beyond a reasonable doubt.”

The jury deliberated for about five hours before finding White guilty, Wold said. “I have never been so demoralized by a verdict,” he said.

Sheila Stately, White’s sister, said that when she learned of the judge’s decision, she cried. “I believe that justice has finally been served. … Our family is very happy and excited that he is coming home.”

A.W. might have some cognitive delay and “some lingering issues” but has been recovering extremely well, Wold said.

Paul Murphy, former chief of the criminal division at the U.S. attorney’s office, said that if the office decides to appeal, it will have to run it by the appellate division of the Solicitor General’s office in Washington, D.C. “District judges don’t take a jury verdict lightly,” he said. “The government is going to have a very interesting decision.”