The black teenagers who threw a pool party in McKinney, Texas, earlier this summer may have been celebrating more than the end of the school year and graduation. Perhaps they were just happy to get a break from police officers in the McKinney Independent School District, who ticket and arrest black students at a much higher rate than others, according to a new report from a Texas criminal justice advocacy group.

In McKinney, the Dallas/Fort Worth suburb where a municipal officer was filmed shoving an African-American girl to the ground and drawing his weapon at the June pool party, blacks make up 13 percent of the student population but got nearly 36 percent of all tickets for offenses such as “disorderly conduct” and "disruption of class" during the 2013-2014 school year, according to the report. "School resource officers" chosen from the ranks of the McKinney police also make arrests. Black students were 39 percent of those youths detained.

The ticketing and arrests are contrary to a law passed by the Texas Legislature in 2013 prohibiting citations for class disruption. Republican Gov. Greg Abbott signed a bill earlier this year that mandates special training for police officers who work in school systems with more than 30,000 students, according to a Huffington Post report.

“McKinney’s extreme and inequitable school discipline measures mirror the larger problems sweeping communities throughout the nation, where inadequate training and racial bias have led to inappropriate and even deadly responses by police in response to minor incidents,” said Deborah Fowler, director of Texas Appleseed, the group that put out the report Wednesday.

In a letter dated Tuesday, Texas Appleseed and the NAACP Legal Defense and Education Fund urged McKinney school and police officials to offer special training for officers assigned to schools. The letter was sent to McKinney Independent School District Superintendent Rick McDaniel, the local school board and Police Chief Greg Conley.

"As the Superintendent of McKinney ISD, we urge you to follow the leadership of Gov. Abbott and the Texas Legislature by supporting the safety and well-being of your students and adopting training policies for police officers in your district’s schools," the group's letter stated.

The McKinney Police Department drew sudden, and unwelcome, national attention in June because of its officers’ response to a teenage pool party in an upper-middle class housing subdivision where some of the teens lived.  Video of the incident, which shows Officer Eric Casebolt pinning a bikini-clad black girl to the ground and drawing his service weapon on other unarmed partygoers, went viral after it was posted to YouTube on June 11. Casebolt has since resigned from the force.