School district officials violated free-speech rights by refusing to display some tiles painted in memory of the Columbine High shooting victims, an attorney for victims' relatives argued Wednesday.

The Jefferson County School District's decision was the equivalent of "unreasonable content discrimination and hostility toward religion," attorney James Rouse said.

School district attorney Alexander Halpern countered that the tile project allowed students to help rebuild the school after the April 20, 1999, massacre left 15 dead, including two gunmen.

He said counselors were warned against turning the project into a memorial for the victims and that the project was never intended as a means of self-expression.

The opening statements came in the trial of a lawsuit filed by six relatives and a friend of victims Daniel Rohrbough and Kelly Fleming. It is expected to last three or four days in U.S. District Court.

The tile project was created in 1996 to allow art students to decorate barren hallways in the newly renovated school. Students were originally instructed to paint the 4-inch ceramic tiles with abstract designs using the school's colors.

After the shooting attack, relatives and friends were invited to paint tiles but were told they could not use the victims' names, initials, date of death or any religious symbol. School officials later made some concessions, for example allowing alumni to paint their class year and allowing realistic representations instead of just abstractions.

Sue Petrone, Rohrbough's mother, testified that she painted a red heart with a yellow cross in it and her son's name even after she was told it violated the rules. "Everything that was in my heart that I wanted to put on the tile, I couldn't do it," she said.

"I couldn't imagine them excluding a memory of my son from that building," she said, crying.

Deidra Fleming, Kelly Fleming's mother, painted two tiles, one with a peace sign and a dove and the other bearing a tree with birds.

She testified that an art teacher told her she could add her daughter's name but it was rejected later.

In the lawsuit, the victims' relatives and friend contend the school district opened a designated public forum and then showed disfavor toward religion.

School district officials contend that the walls are a limited public forum and the tiles are defined as symbols, not speech.