Cross burnings may seem like a relic from a dark chapter in American history, but an incident in Indiana resulted this week in prison sentences of a year or more for three Muncie men.

At least two other Indiana cross-burning cases, in Muncie and Mishawaka, have been prosecuted in the past two years. All three were motivated by racism, federal prosecutors say.

During a Friday visit to Indianapolis, the top civil rights lawyer for the U.S. government pointed to those cases and increases in reported hate crimes as reason for vigilance. Thomas E. Perez, confirmed by the U.S. Senate last month as assistant attorney general for the Department of Justice’s Civil Rights Division, cited a recent expansion of the federal hate-crimes law as an important tool.

“Recent history here in Indiana and across the nation reminds us that we continue to have people who, frankly, have issues with the diversity of our country and with the inclusion that is our nation’s strength,” Perez said during a news conference with other federal officials, including acting U.S. Attorney Tim Morrison.

The case that ended this week was spurred by a cross set afire in a yard in July 2008 as a black family slept inside their home in a Muncie neighborhood. Sentenced Thursday were Richard LaShure, 41; his son, Richard Logue, 20; and Aaron Latham, 20.

During an interview with The Indianapolis Star, Perez, 48, said crimes tinged with hatred deserve serious treatment.

“Hate crimes are different because they reflect the desire not only to break the bones or spirit of the individual, but also to break the spirit of the community at large,” Perez said.

Last week, President Barack Obama signed a bill expanding the 40-year-old federal hate-crime law to add protections based on sexual orientation, gender, gender identity and disability. It also gives federal authorities leeway to prosecute more cases and aid local investigations.

In Indiana, one of five states without a state hate-crime law, federal authorities often step in or assist state and local police. Michael Welch, special agent in charge of the FBI office in Indianapolis, said his agents handle the fifth-largest volume of hate-crime investigations, compared with offices of a similar size.

More than 30 civil rights-related investigations are under way in Indiana, Welch said.

In 2007, the most recent year for which data are available, the FBI received 7,624 reports of hate-crime incidents from police agencies, down slightly from 2006. But crimes motivated by sexual orientation and against Hispanics were up.

Perez praised the Bush administration’s aggressive stance on hate crimes as well as religious discrimination, human trafficking and compliance with bilingual ballot requirements.

But he criticized the Justice Department’s handling of civil rights issues under the Bush administration, which he said had politicized the division. Perez said the Obama administration would return to a nonpartisan tradition.

One shift under the Bush administration was on affirmative action issues. In Indianapolis, that meant an end to a 30-year-old consent decree that had set hiring and promotion targets to boost the ranks of minorities and women in the Fire and Police departments.

Perez declined to address the Indianapolis case but said his division would monitor such issues.

“We’ll continue to enforce the laws that are on the books,” he said. “Our mission is to ensure that they hire the most qualified people and that they have programs in place that don’t discriminate.”