The sheriff's deputy charged with failing to protect students during the mass shooting in a Parkland, Florida high school has a simple defense, some legal experts said - he did not have a duty to save the victims.

"There's no crime called refusing to die while a mass murderer is in your school," said Eugene O'Donnell, a former New York City police officer and prosecutor who teaches at the John Jay College of Criminal Justice.

Scot Peterson, 56, was arrested on Tuesday on charges of child neglect, negligence and perjury, and is in jail on $102,000 bond. He has not yet entered a plea but his lawyer says he will "vigorously" fight the charges, reports Reuters.

Several law professors and defense lawyers said they were unaware of a previous case in which a law enforcement officer had been charged for failing to take an action.

The neglect law that Peterson is accused of breaking is usually used to prosecute caregivers such as parents and daycare providers. Peterson has a strong defense that the statute does not apply to law enforcement officers, according to several legal experts.