It's the latest fallout from the $6.7 million fraud trial of charter-school founder Dorothy June Brown and other administrators, which is scheduled to begin Wednesday.
"We suspect the Lab [board of trustees] has materially participated to obstruct/delay the trial of Dr. Brown's codefendants . . . by using school-related public funds to pay legal fees for codefendants to file their motions to dismiss," parents wrote in an Oct. 25 letter to Assistant U.S. Attorney Frank R. Costello Jr., one of the two prosecutors handling the case.
Patricia Hartman, a spokeswoman for the U.S. Attorney's Office, declined comment.
Through its lawyer, Scot R. Withers, the board said requests for payment of legal fees are acted on at public meetings and handled according to state law.
The letter to prosecutors reflects the concerns of parents worried because the charter renewal for the award-winning Lab - and another school Brown founded - has been on hold since the federal indictments were announced in July 2012.
Laboratory, a K-8 school with campuses in Northern Liberties, Overbrook, and Wynnefield, was recently named a 2013 National Blue Ribbon School by the U.S. Department of Education.
To date, the school's board has authorized spending up to $250,000 to represent Slade, Brown's great-nephew, who is facing multiple counts of obstructing justice.
On Oct. 16, the board voted to table a request from Slade's lawyers to set aside up to $192,000 more after several parents objected.
Slade, who was suspended with pay after being indicted, also continues to collect his salary, which was $168,000 in 2012.
In the letter to the U.S. Attorney's Office, parents said they were concerned that the board's actions were driving the school toward insolvency, and threatening the rights of 500 children to a high-quality public education.
Withers said Slade's legal bills had not exhausted the initial amount, but his lawyers said they expected they will need more money during the trial.
Brown, a former Philadelphia School District principal, founded three small K-8 charter schools in the city. In addition to Laboratory, she created Ad Prima, which has campuses in Overbrook and Frankford; and Planet Abacus, in Tacony. She also founded Agora Cyber Charter in 2005, but cut her ties with it in 2009 as part of a settlement involving several civil suits, including one from the state Department of Education.
Slade's expenses are only part of the costs that charter schools in Brown's network are shouldering to defend suspended staffers charged with participating in a scheme to defraud the schools and then trying to cover it up.
In addition to Slade, charter school boards have agreed to spend up to $550,000 to defend two other employees.
Withers, who represents the boards of all three of Brown's charter schools, said payments to defense lawyers are authorized under the state's nonprofit law.
Under agreements the indicted employees have signed, they could be required to repay the money if the boards later find they did not act in the schools' best interests, Withers said.
The boards of Ad Prima and Laboratory have each approved spending $125,000 to defend Courteney L. Knight, a Lab teacher and a former chief executive of Ad Prima.
Planet Abacus approved $300,000 for Joan Woods Chalker, a top lieutenant in Brown's school network who had worked with Brown for more than 20 years and had been chief executive at Planet Abacus.
Chalker also had requested $192,000 from Laboratory, where she previously worked. Withers said her lawyers asked for the money to defend Chalker on charges she took part in a scheme to collect unused vacation and sick pay from Lab that she was not entitled to receive.
The board did not act on Chalker's request at an Oct. 16 meeting. Five days later, she pleaded guilty to three counts of obstructing justice.
As a result of the guilty plea, Planet Abacus has suspended payments to Chalker's lawyers, Withers said.
He said the board cannot determine yet whether Chalker will be required to repay her legal expenses because her plea agreement has been sealed by the court.
She had been receiving her $137,000 salary as the suspended chief executive of Planet Abacus until she resigned in March.
Knight remains an instructor at Laboratory. Records from the state teachers' retirement system show that he was paid $57,046 annually in 2012.
Withers said Knight was not suspended because he no longer held a management position.
He said Laboratory and Planet Abacus had reached agreements with the district on the terms of their charter renewals and hoped those would be voted on at a Nov. 21 meeting of the School Reform Commission.
"We are very pleased the negotiations with the charter schools are moving forward," district spokesman Fernando Gallard said.
He said he could not discuss the proposed conditions or say whether the SRC would consider the renewals this month because negotiations are continuing. In other cases involving allegations of wrongdoing or financial mismanagement at city charter schools, the SRC has required the schools to replace their boards as a condition of renewal.