Abigail Hernandez, 21, from Rochester City School District has been arrested after she threatened to shoot up a school in Upstate New York

A 21-year-old student from Rochester City School District has been arrested after she threatened to shoot up a school in Upstate New York.

Rochester Deputy Mayor Dr. Cedric Alexander and Deputy Chief La'Ron Singletary spoke at a news conference Friday afternoon where they said Abigail Hernandez made a credible threat against East High School.

Hernandez is not a student at East High School.

Police were notified on February 16 by a member of staff after Hernandez wrote on Facebook 'I'm coming tomorrow morning and I'm going to shoot all of ya bitches,' according to WJLA.

Apparently it took investigators days to arrest track down because she made the threats from a fictitious social media account.

When officers went to the home of Abigail Hernandez on Tuesday, they said they found a shotgun inside the home.

It was not clarified whether the shotgun belonged to Hernandez. However, she was arrested and charged with making a terrorist threat.

She was remanded to the Monroe County Jail at the time in lieu of $15,000 bail.

During the investigation Immigration and Customs Enforcement (ICE) agents discovered that Hernandez was an illegal immigrant who was in the United States under the Deferred Action for Childhood Arrivals (DACA) program.

Hernandez is not a student at East High School (pictured here) but threatened to shoot up the school via a post on Facebook that read 'I'm coming tomorrow morning and I'm going to shoot all of ya bitches'

Video courtesy WHAM

The DACA program was created under the Obama administration in 2012 and states that certain people who were brought to the US as children and meet a series of strict guidelines will be eligible to have deferred action for at least two years.

Hernandez was moved to a federal detention facility in Batavia and will be held there until a hearing is scheduled.

'The quick thinking of school staff and the tenacious work of the investigators of the police department following through on this Facebook post lead to the arrest of Abigail Hernandez and the recovery of a shotgun,' a statement from the Rochester Police Department said.

She was remanded to the Monroe County Jail at the time in lieu of $15,000 bail

East High School Superintendent Shaun Nelms released a statement Friday evening: 'Sadly, in wake of the recent Parkland, Florida tragedy, schools across the country have been grappling with social media threats intended to instill fear and anxiety. While we cannot comment on this particular police investigation around a threat made to East, I want to stress how fortunate we are to be part of a community in which the police department works closely with schools to ensure the safety of the entire school community.'

'We remain very grateful to the Rochester Police Department for their partnership and for keeping us well informed throughout the entire process. Their presence on campus last week and their guidance on how to best keep staff and students safe during this efficient, successful police investigation reiterates their ongoing support. As always, the safety of students and staff is our top priority.'