WAUKESHA, Wis. -- The Waukesha County Sheriff's Department said a deputy shot and wounded an inmate in a hospital after the inmate threatened him with a knife.

Steven P. Lettenberger, 43, was in critical condition Friday. A hospital spokeswoman said Saturday she had no listing for Lettenberger, speculating that his information had been rendered confidential.

The sheriff's department said Lettenberger was at the hospital for treatment Friday afternoon when he somehow armed himself with a knife. Authorities said he tried to attack the deputy who was guarding him.

The deputy then shot Lettenberger, who had been in custody for endangering safety and carrying a concealed weapon.

A message left for Lettenberger's attorney Saturday wasn't immediately returned.