Giving preference to Muslim clothing rules. Girls, but not boys, are prohibited from wearing short sleeves. Girls also must wear skirts or pants of a certain length, depending on their grade level. Female teachers must be covered from neck to wrist and ankle.
The lawsuit also accuses the state Education Department of giving the school public money despite repeated violations of state law.
Chas Anderson, the department's deputy commissioner, said in a written statement that state law requires charter schools to remain nonsectarian and state education officials take that requirement seriously.
"The department is in the process of carefully reviewing the ACLU lawsuit and will thoroughly respond through the legal process," Anderson said.
"We will continue to monitor the operations of TiZA Academy and, in response to issues raised about the school over the past year, we are in the process of drafting legislation to address these concerns."
This isn't the first time TiZA has attracted public scrutiny. Last year, a columnist for the Minneapolis-based Star Tribune wrote that the school mixed the roles of religion and public education. Katherine Kersten's column aired a substitute teacher's allegations that school officials promoted Islam in the classroom.
That sparked the investigation by the state Education Department. In May, department officials recommended the charter school modify its communal prayers on Fridays and provide after-school busing at different times for students who aren't participating in religious activities.
School officials have said they have taken corrective actions. They also said they received numerous threats and hate mail after the newspaper column ran.
TiZA students, many of them recent immigrants, have had better-than-average success on state-required exams.
At the Inver Grove Heights campus, 86 percent of students are from low-income families and about 70 percent are English language learners, according to state data for the 2006-07 school year.
In 2008, 80 percent of the students were proficient in math, compared with the statewide average of 66 percent.
Joe Nathan, director of the Center for School Change at the University of Minnesota, said the ACLU should be praising the charter school, not suing it.
Nathan said he has spent many hours at TiZA doing research and saw nothing to suggest the school was promoting a single religion. In his 35 years as an educator, Nathan said, he would put TiZA in the top 5 percent of schools he has reviewed in terms of academic excellence and commitment to tolerance.
"As an American Jew who strongly believes in the separation of church and state, if I thought this was a school that was crossing the line and teaching religion, I wouldn't support it," he said. "This school is a model of results, diversity and tolerance."
But Samuelson said TiZA's practices are still violating constitutional law.
"However well-run and academically challenging a religious school may be, it is unconstitutional for public funds to be used for religious education," he said.
The lawsuit comes at a time when state lawmakers say scrutinizing and tightening rules for charter schools is at the top of their legislative agenda.
Proposed changes include requiring sponsors to better monitor their schools' financial and academic performance, reducing board members' conflicts of interest and clarifying how charters can spend money they receive for leasing space.
"It is critical that the Legislature ensure that charter schools are run in the most accountable, efficient and transparent way possible," said Sen. Kathy Saltzman, DFL-Woodbury, who is chairing a task force tackling charter school issues this session.
"Without better oversight, the public's confidence in our charter schools is in jeopardy," she said.
Maricella Miranda contributed to this report. Megan Boldt can be reached at 651-228-5495.
A lawsuit filed by the ACLU of Minnesota claims Tarek ibn Ziyad Academy and the Muslim American Society of Minnesota are linked by a "complex, interconnecting set of personal, corporate and operational relationships." According to the suit, they include: