The Congressional Black Caucus is asking the Justice Department to investigate possible civil rights violations in the "Jena 6" case that sparked a massive protest in Louisiana last week.

"This shocking case has focused national and international attention on what appears to be an unbelievable example of the separate and unequal justice that was once commonplace in the Deep South," the group of 43 lawmakers said in a letter to Acting Attorney General Peter Keisler.

Justice Department spokesman Brian Roehrkasse said the department has been closely monitoring the case of six black high school teens arrested for beating a white classmate in Jena, La. He said the department also is investigating allegations of threats against the students and their families.

"Since these investigations are ongoing, the department cannot comment any further," Roehrkasse said.

Top Justice officials were set to discuss the case on Friday with civil rights leaders, including the Rev. Jesse Jackson and National Urban League President Marc Morial.

The caucus also sent a separate letter asking Louisiana Gov. Kathleen Blanco to pardon 17-year-old Mychal Bell, the black teen convicted in adult court of aggravated second-degree battery after the charge was reduced from attempted murder.

Bell, who remains behind bars, was one of six Jena High School students arrested after a December attack on a white student, Justin Barker, and the only one to be tried.

Bell was tried as an adult and convicted of aggravated second-degree battery after the charge was reduced from attempted murder. A state appeals court recently threw out his conviction, saying he could not be tried as an adult.

District Attorney Reed Walters said Thursday that he would not appeal that decision and would let a juvenile court deal with the case.

The black lawmakers call the decision to charge Bell and his classmates as adults "an abuse of prosecutorial discretion" and claim no action was taken in a recent similar case involving a white defendant and a black victim.

"The failure to grant bail to Mychal Bell is harsh, to the point of being unconscionable, given all the facts that have come to our attention," the lawmakers wrote to Blanco.

More than 20,000 people converged on the small town last week to protest the case, accusing local officials of prosecuting blacks more harshly than whites.

The case dates to August 2006, when a black Jena High School student asked the principal whether blacks could sit under a shade tree that was a frequent gathering place for whites. He was told yes, but nooses appeared in the tree the next day.