Charter school founder Dorothy June Brown suffers from Alzheimer's-like dementia and is incompetent to be retried on fraud charges, a federal judge has found.

In an order entered Monday, Judge R. Barclay Surrick granted a motion from the U.S. attorney and dismissed the indictment charging that Brown had defrauded the schools she founded of $6.3 million. Defense attorneys concurred.

Based on reports of four medical experts, Surrick found that a preponderance of evidence showed that Brown could not stand trial because she "is unable to understand the nature and consequences of the proceedings against her and to assist properly in her defense."

Brown, 78, who founded three small charter schools in Philadelphia and a cyber school in the suburbs, had been charged with scheming to defraud the schools and conspiring with four other administrators to cover up the alleged crimes.

But in a motion submitted to Surrick, U.S. Attorney Zane David Memeger and two federal prosecutors asked for the charges to be dropped.

"Under these extraordinary circumstances," he wrote, "the government is compelled to conclude that it is in the interests of justice to dismiss the indictment against defendant Brown due to her mental condition."

The government, he said, did not believe that Brown "will be competent to stand trial at any point in the near future, if ever."

Patricia Hartman, spokeswoman for the U.S. Attorney's Office, said the government had no choice but to ask the court to drop the outstanding charges.

"Because all of the experts determined that the defendant was incompetent to stand trial, there was no alternative but for the court to dismiss the indictment," she said.

Monday's ruling ends a saga that began with Brown's initial indictment in July 2012, a hung jury on several counts in January of 2014, and an earlier competency hearing, after which Surrick found in April that Brown suffered from some memory lapses, but was competent to be retried.

In June, as that retrial loomed, Brown's attorneys filed additional medical information based on her examination by doctors in Cleveland.

Brown's husband had taken her to the Cleveland Clinic's Lou Ruvo Center for Brain Health Neurological Institute 11 days after the judge's April ruling, saying he was concerned about his wife's "deteriorating mental condition."

Brown's retrial was continued. Surrick ordered her to undergo further examination. Susan Rushing, a forensic psychiatrist selected by the government, ran additional tests, performed a new evaluation, and reviewed all the prior medical records and reports.

Rushing concluded that Brown was suffering from dementia and was "unable to maintain a rational and factual understanding of the proceedings against her."

The report was filed under court seal on Aug. 12. Surrick referenced the findings in his ruling and memorandum Monday.

Two codefendants pleaded guilty and testified against Brown during her trial, from October 2013 to January 2014. Brown was acquitted on six counts, and jurors deadlocked on dozens of others, causing prosecutors to seek a retrial.

martha.woodall@phillynews.com 215-854-2789 @marwooda