Correspondent Raj Chohan of CBS Station KCNC-TV in Denver reports that Darnay Hoffman filed a suit Wednesday in an effort to testify before the grand jury investigating the murder of the 6-year-old beauty-pageant winner.
Hoffman says handwriting experts can prove that JonBenet's mother, Patsy, wrote the ransom note that was found in the Ramsey home the day JonBenet's body was discovered.
Hoffman said he tried to get handwriting experts David Liebman and Cina Wong to testify before the grand jury but was prevented by Boulder District Attorney Alex Hunter. He said both have agreed to testify without charge.
Hoffman is asking a Boulder District Court judge to force Hunter to allow them to testify about the handwriting before the grand jury.
A judge earlier dismissed Hoffman's bid to force prosecutors to file criminal charges in the slaying, saying there was no evidence Hunter was refusing to prosecute the case.
JonBenet was found beaten and strangled in the basement of her home on Dec. 26, 1996. Her parents have denied killing her, and no one has been charged in the murder.
The Boulder grand jury, impaneled earlier this year amid controversy, is meeting for a sixth day Thursday to hear testimony from police officers who were at the crime scene.