BOZEMAN, Mont. -

A judge has ruled a former Gallatin County deputy can be tried on a charge of mistreating a prisoner, but the state cannot present video of him grabbing the teenager by the throat and pushing her against the wall because investigators did not preserve all of the video pertinent to the case.
    
Former deputy Thomas Madsen had asked that the charge be dismissed. District Judge Holly Brown denied that motion on Tuesday, but said investigators were negligent because they only preserved a copy a few minutes of the video taken while the girl was in an interview room in February 2011.
    
Brown said the video cannot be mentioned at Madsen's trial, which is scheduled to start on July 17.
    
The state is reviewing whether to appeal Brown's ruling.