Smithfield — A woman charged Wednesday with robbery and murder in the death of a Benson-area man has also been charged with assaulting a Johnston County deputy, officials said Thursday.

Sheriff's spokeswoman Tammy Amaon said Detective Brandon Harris was transporting Nancy Hernandez to the sheriff's office for questioning about noon. Amaon said detectives had labeled Hernandez as a "person of interest" in the death of 62-year old Bobby Glenn McLamb of N.C. 242. But at the time she was detained, Hernandez had not yet been charged with any crime, Amaon noted.

As Harris drove down Brogden Road, he looked in the back seat of his patrol car and noticed that Hernandez, 48, of 6928 Godwin Lake Road, Dunn, had wielded a knife. Amaon said Harris abruptly stopped and exited his car. He called for police backup, and within a few minutes, a Smithfield police officer arrived to help.

Amaon said Hernandez also got out of the patrol car, and when Officer S.M. Greer arrived, she lashed out at Greer. Police in Smithfield said Hernandez then lunged at Greer with the knife. Greer used his Taser to subdue her.

Hernandez was charged with assaulting Harris. But because Greer was only assisting another police agency, he did not file similar charges.

Records show Wednesday's incident was not Hernandez's first time attacking a law enforcement officer. Clayton police charged Hernandez in July 2007 with communicating threats and assaulting a government official.

Officers in Clayton also charged Hernandez in December for intoxicated and disruptive behavior, a misdemeanor. Court records show Hernandez missed her court date for that charge. Sheriff deputies added to her list of charges this week a charge for failing to appear for her scheduled hearing.

Meanwhile, investigators are also probing whether or not Hernandez's son is responsible for stealing a truck from a Godwin Lake Road business. Amaon said Douglas Tart, owner of Across the Lake Farming Company Inc., told authorities he found a company truck in a ditch when he arrived at work Wednesday morning.

Amaon said detectives think Luis Hernandez, 27, might be responsible for the attempted theft of Tart’s 1997 Nissan pickup. Luis Hernandez has not been charged in that incident. But Luis Hernandez and his girlfriend, Amanda Russell, 26, have also been charged in connection with McLamb's murder.

All three suspects remain in the Johnston County jail without bond.