A government official says prosecutors are considering a conspiracy charge against the son of an Indian tribal leader in last week's deadly school shooting, but federal authorities refuse to say what role the teen may have played in the killings.

Louis Jourdain, 16, the son of Red Lake Band of Chippewa Chairman Floyd Jourdain Jr. (search), appeared in federal court in Duluth on Tuesday. The hearing was closed to reporters and court officials would not comment because it was a juvenile proceeding.

A government official briefed on the investigation told The Associated Press that prosecutors were considering charging the teen as an adult with conspiracy to commit murder. That official spoke on condition of anonymity because the investigation is ongoing.

The Washington Post, citing family members and law enforcement officials, reported the conspiracy charge was already filed.

Jourdain's attorney, Jon Hopeman, told the AP he could not comment because it was a juvenile proceeding.

Jeff Weise (search), 16, killed his grandfather and the grandfather's companion, then went to Red Lake High School (search) and killed five students, a teacher and a guard, before killing himself. It was the worst U.S. school shooting since the attacks by a pair of students at Columbine High (search) in Colorado in 1999.

In announcing Jourdain's arrest Monday, U.S. Attorney Tom Heffelfinger would not give any details on the youth's role in the case.

Weise and Jourdain were members of a clique of about five students known as "The Darkers," who wore black clothes and chains, spiked or dyed their hair and loved heavy-metal music, according to the Minneapolis Star Tribune, the St. Paul Pioneer Press and the Duluth News Tribune.

Two students, Jourdain Warmington, 15, and Jazz Jourdain-Warmington, 14, told the Minneapolis newspaper that when the shootings started they were in the library and that Jourdain yelled that the shooter was Weise — before anyone in the library saw the gunman. The two girls' relationship to each other and to Jourdain was not immediately clear.

Jourdain-Warmington said Jourdain ran out of the library, saying he had to talk to Weise.

Authorities began to suspect Weise may not have plotted the attack by himself after examining his computer and the e-mails he exchanged with Jourdain, said the government official who asked to remain anonymous.

The New York Times reported Tuesday that an official who spoke on the condition of anonymity said the e-mails suggested Weise and Jourdain planned an attack on the school, with graphic discussions about logistics and targets. The official also said Jourdain had told investigators that he never had any intention of going through with the plan and that he did not believe Weise did, either, the paper reported.

Floyd Jourdain said he was confident an investigation would clear his son.

"It is with optimism that I state my son Louis's innocence," Floyd Jourdain Jr. said in a statement. "He is a good boy with a good heart, who never harmed anyone in his entire life."