A former middle school teacher was charged Thursday with stalking students by leaving threatening notes, including one that read, "Tick-tock, tick-tock, is it a bomb or is it a clock?"

Michelle Dohm, 40, denied the allegations through her attorney, Thomas Morrow. He said Dohm believes she was framed.

"She had no motive to commit any wrongdoing, she didn't have the ability to commit any wrongdoing and she intends to vigorously deny the charges," the lawyer said.

Dohm was fired from her job as a sixth-grade social studies teacher in mid-November, Frederick County State's Attorney Scott Rolle said.

The sheriff's office planned to arrest her after getting a warrant based on the grand jury indictment, Cpl. Jennifer Bailey said.

The indictment charged Dohm with nine felony counts of threatening to explode a destructive device and two misdemeanor counts of stalking. The charges carry a maximum 100 years in prison and $100,000 in fines.

Dohm is accused of leaving or delivering threatening notes on at least five occasions from Sept. 28 through Nov. 21. The last note, found in the boys bathroom, prompted an evacuation of the school.

According to Rolle, it read: "Tick-tock, Tick-tock, now you'll know it's a bomb and not a clock. At 12 o'clock you'll know I wasn't kidding."

The messages targeted four male students, and investigators learned that they had been printed from Dohm's school computer, Rolle said.

In her exit interview with the school superintendent after she was fired, Dohm said that if another note were found, it would prove she wasn't to blame. The last note was found in the boys bathroom a week later, Rolle said.

Dohm taught in Frederick County schools for 18 years, a school system spokeswoman said.