Brockton Public Schools, embroiled by chaotic student behavior at its high school, finds itself in even more financial trouble as its budget deficit could grow as large as $25 million.

The staggering development came to light Friday when officials released the findings of a third-party, independent review of the district’s budget the School Committee ordered last summer after discovering a $14.4 million deficit the previous fiscal year.

Open Architects, a Boston-based software company specializing in education data, completed the review in February, anticipating Brockton’s budget projected to exceed its $231.1 general budget this year by at least $19 million and at most $25 million.

Issues with transportation and special education spending and general budget oversight are the primary drivers behind the overspending, the third-party review found.

Mayor Robert Sullivan, in a release, called the report a “major step toward understanding the root causes of the school department budget deficit.”

“The issues identified in the report are unacceptable,” he said. “The city is taking action — with guidance and assistance from the Commonwealth — to address these issues in the short term and implement safeguards to ensure that nothing like this happens again.”

Transportation costs are soaring well past the budgeted $11.2 million, with final spending likely to be in the ballpark of $22.5 million. The district has insourced services in recent years, but officials “never created a proper budget to account for the full cost of services,” Open Architects said.

Additionally, the review found the district liable for $1 million in costs associated with the unmet needs of special education students, district officials highlighted in a release. Massachusetts districts are responsible for placing students in schools where their needs can be met.

Glaringly, the district “failed to properly use” a specific budget software that tracks spending, “including the failure to properly classify line items or update the system to reflect the true budgeted amounts of certain line items, including transportation,” officials wrote in the release on the report.

“This lack of oversight especially impacted the management and spending of grants, allowing for accounts dedicated to finite grant funding to be overdrawn,” they wrote.

“Like with any of the challenges facing our city and our schools, there’s no one-size-fits-all solution,” Acting Superintendent James Cobbs stated in the release. “However, this report provides us with critical insight into where we’ve gone wrong and a roadmap for improving our processes.”

Cobbs took over as the district’s top leader at the time the School Committee authorized the budget review, just days before this academic year began.

Superintendent Mike Thomas, who has been in the district for 30 years, informed the committee last fiscal August he’d be out on extended medical leave when they learned about the “unexpected” $14.4 million deficit that grew to $18.3 million in the previous fiscal year.

To close last fiscal year’s budget and set the tax rate, officials allocated $19 million to cover the deficit, using the entire $7.9 million stabilization fund that requires replenishment and an interest charge for its use, $2 million from free cash and $9.1 million in local receipts, the review states.

The forecast is not bright for the upcoming fiscal year, beginning in July, with the review finding that even after a projected $19 million increase in state funding, the district is likely to face at least a $7 million deficit.

This is all coming as Brockton High School has reached the national limelight for a “disturbing increase in incidents related to violence, security concerns, and substance abuse.”

The unruly student behavior prompted four School Committee members to request the National Guard to be deployed to Massachusetts’ largest high school to address the issues. But Sullivan and Gov. Maura Healey, who has sole authority over the Guard, opposed the measure.

School Committee member Tony Rodrigues appeared on Fox Business last month, highlighting how he believes the district’s massive budget deficit has played a large role in setting the stage for the disruptive scene at the high school.

At least 20 to 25 teachers are calling out of work a day on average, leading to 800 students roaming around the halls unsupervised, Rodrigues said on the Feb. 21 edition of The Bottom Line.

“We have to have the bodies inside the school,” he said. “Right now what you do is when you have a lot of educators not in the building, these kids are free to roam. And what do you think these teenagers are going to do? It’s free for all.”

Months before his leave, Superintendent Thomas announced that 130 certified staff positions would be eliminated due to an $18 million deficit in the 2023 fiscal year’s budget, citing how nearly 1,350 students had left the district since the start of the pandemic.

Thomas, who earned a gross pay of $271,132 in 2022, has taken “full blame” for the budget debacle, saying he did not embezzle money and that there are no missing dollars.

He told the district on Feb. 21 that he was “well enough to return to work” and that he rescinded his leave, but the School Committee instead voted to place him on paid administrative leave, the Brockton Enterprise reported.

“It’s unfortunate you pay me all this money to have me sitting out when you know I could make a difference,” Thomas told the School Committee on Feb. 27. “If Mike Thomas was here, this stuff at the high school you know would not be happening. Not a chance.”