The Arizona Attorney General's Office is suing the Arizona Board of Regents for "dramatically and unconstitutionally" increasing the price of in-state tuition at the state's three universities by as much as 370 percent over the past 15 years.

The suit, filed Friday in Maricopa County Superior Court, says the increases violate the Arizona Constitution, which states that university instruction shall be furnished "as nearly free as possible." Over the past 15 years the regents raised tuition from about $2,600 a year to as much as $12,228 a year for in-state students, the suit said.

The move comes after the Attorney General's Office warned in July that the state universities may be spending public money improperly because the regents continue to give in-state tuition to migrant students known as "dreamers," despite a court ruling that said the practice violated state law.

The Attorney General's Office sent a letter to the regents after the Arizona Court of Appeals ruled in June that state law bars colleges from granting in-state tuition for students in the federal Deferred Action for Childhood Arrivals program, known as DACA.

About 240 current DACA students at the state's universities are receiving in-state tuition rates, which are substantially cheaper than non-resident rates. The in-state rate for undergraduate students at Arizona State University is $10,792 this year, compared with $27,372 for non-resident students.

The main thrust of the lawsuit filed Friday, however, objects to the regents' overall tuition-setting policy.

Attorney General Mark Brnovich, in remarks to the media on Friday, said the in-state tuition for DACA students gave the office a "vehicle" for looking at the way regents decide tuition rates in general.

He said the formula the regents use is "not consistent" with the "nearly free" mandate of the state Constitution.

Rather than basing tuition on the cost of furnishing instruction, the suit contends the regents also compare Arizona tuition with "peer universities" and the availability of student aid. The regents also "misinterpret" the state Constitution's "nearly free" mandate to mean "affordable," the suit said.

"With its unconstitutional tuition-setting policy, ABOR has abandoned its duty to serve as a check on the university presidents, and has engaged in an unprecedented series of lockstep tuition hikes across Arizona's three public universities that has resulted in a tuition increase of over 300 percent at each school," the lawsuit said.

The suit goes on to say that the regents also unlawfully charge students who attend part time or online "significantly more than actual cost," and require them to pay for things other than instruction such as athletic, recreation, technology and health fees.

ROBERTS: Brnovich sues over high tuition costs (finally)

The suit contends in-state mandatory tuition and fees have increased as follows since 2002-03 when rates averaged about $2,600:

University of Arizona: $12,228, or 370 percent increase.

Northern Arizona University: $11,059, or 325 percent increase.

Arizona State University: $10,792, or 315 percent increase.

The regents released a statement on Friday afternoon, saying the board has not yet been served with a copy of the lawsuit and will meet to get legal advice during an executive session on Sept. 11.

The regents were last sued over tuition in 2003, when four UA students filed suit after the board raised tuition 39 percent in a single year, citing the "nearly free" provision.

But the suit was dismissed in 2007 when the Arizona Supreme Court ruled that the tuition increase was a political question, not a judicial one.

The regents have said previously that tuition increases have been necessary to continue providing quality education. They have maintained that sharp increases were needed during the recession, to help offset steep cuts in state funding.

At the same time, enrollment has continued to increase. The university system has added 49,060 students since 2008 for a total of 171,791 students in fiscal 2017.

The regents said earlier this year that state funding covers about 34 percent of the cost of educating in-state students, down from 75 percent in 2008.

Before the recession, the state university system received about $1 billion a year from the state.

A series of budget cuts during the recession have resulted in $390 million less a year in general fund revenues compared with 2008, according to data compiled by the nonpartisan Joint Legislative Budget Committee.

Reach the reporter at 602-444-8072 or anne.ryman@arizonarepublic.com.