AUGUSTA, Maine — Portland’s mayor is asking Maine’s attorney general to investigate allegations of mismanagement at the Baxter Academy for Technology and Science. The charter high school’s board of directors cited those allegations earlier this month in dismissing John Jaques, the school’s founder and former executive director.

In a letter sent to Attorney General Janet Mills on Friday, Portland Mayor Michael Brennan said management changes at the school, which is expected to open in September, have “raised serious questions about its viability as well as concerns over the application process and subsequent approval granted by the Maine Charter School Commission.”

Until the matter is settled, Brennan has asked Portland Schools Superintendent Emmanuel Caulk to withhold school district payments to the independently run school for any Portland public school students who attend next school year.

Brennan’s letter came two weeks after the Baxter Academy board forced out Jacques, citing “finances proposed within Baxter Academy’s budget [that] were never put into place” and “a pattern of mismanagement.”

Jaques disputed the claims, saying the board removed him at the request of a potential donor who promised the school $250,000. Following his dismissal, Jaques cut off the Baxter board’s access to the school website, email and documents, saying he personally owned the intellectual property.

The board has since started a new website with a different domain name.

In addition to investigating the claims of mismanagement at the school, Brennan, in his letter, asks Mills to determine whether the Maine Charter School Commission “conducted an appropriate review” of the school’s financial picture before granting its authority to open. He also asked the attorney general to examine whether the commission offered any inappropriate advice or assistance to the charter school during the application process.

Baxter Academy gained approval from the Maine Charter School Commission in July 2012 on the condition it open in September 2013. The school is now set to open Sept. 3, and Allison Crean Davis, the board’s vice chairwoman, said earlier this month that the school has letters of intent from 158 students from throughout southern Maine with more on a waiting list.

Brennan has long opposed Baxter Academy’s plans to open in Portland and offer a curriculum focused on the STEM disciplines of science, technology, engineering and math. The mayor has argued the school doesn’t offer the city’s students any opportunities they don’t already have, and he’s said the school will divert precious funds away from the Portland Public Schools budget.

Charter schools are public schools of choice that operate independently of local school districts. Maine became the 41st state to allow charter schools following a law that passed the Republican-controlled 125th Legislature in 2011. For every student it enrolls, a charter school receives a tuition payment from the student’s home school district.