U.S. Attorney John Suthers on Thursday rejected a request from the families of slain Columbine victims to convene a grand jury to investigate claims that a student was killed by police.

"There is not a scintilla of evidence to suggest that any such action was willful or intentional, which is the standard for a federal criminal prosecution," Suthers said in a written statement.

The parents of slain student Daniel Rohrbough claim a Denver police officer killed the 15-year-old as he ran from the school on April 20, 1999. Police say student gunmen Dylan Klebold and Eric Harris killed Rohrbough and 12 others before killing themselves.

Suthers said that even if there was evidence linking the officer to Rohrbough's death, he still would not call a grand jury.

He also said there is no evidence of a criminal conspiracy. Some of the victims' families have claimed the Jefferson County Sheriff's Department lied about their investigation.

Suther's announcement comes a week after a federal judge refused to reconsider lawsuits brought by the Rohrboughs and other families in light of the new allegations. County prosecutors also have refused to look into the allegations, and a county coroner rejected a request for an inquest into Rohrbough's death.