Updated at 7:45 p.m. to include comments from a parent.

Staff members at a Garland charter school are outraged over the handling of a school shooting threat that was kept quiet last week.

Several teachers and parents from Garland Classical Academy said the school's director did not tell them about a former student who was arrested after threatening to shoot up the school, which serves students in kindergarten through the eighth grade.

"I was devastated by how this was handled," said Pamela Bounds, a reading intervention specialist at the school. "How could you know this for almost a week and not let us know this and not let the parents know this?"

Earnest Oldham, a father of seventh-graders, said he and his wife plan to withdraw their twins from the school after the end of the semester over the way the threat was handled. Oldham, who works in law enforcement, said parents should have been notified of the threat immediately.

"We're really disappointed how things have gone," he said. "There are things that happened that I'm absolutely horrified of."

According to the teachers, on April 10, a student showed administrators social media videos of the former student posing with guns and saying he was going to shoot "everyone at the school who made his life miserable." The teen was asked to leave the school earlier this year.

Garland police said the juvenile was arrested at his home that evening after they were notified of the threat. He isn't being identified because of his age.

Although the student had only toy guns in his possession, police spokesman Alberto Irizarry said, he could face charges for the fear he provoked by posting the threatening videos.

The school's corporate office said in a written statement that the school notified police about a former student who "was alleged to have made claims about coming to the school and causing harm to an individual."

Teachers said staff, parents and students were not notified of the threat until six days afterward. They were sent a letter Monday from the school's director, Tiffany Linwood, that simultaneously announced that the school's assistant director was no longer working at the school and addressed the threat from a week earlier.

"Assistant Campus Director George Trull is no longer employed with ResponsiveEd and Garland Classical Academy," the letter said.

The letter did not say that his exit was connected to the threat, and the school's corporate office declined to comment the issue.

Teachers and parents, including the Oldhams, said it seems strange that Trull, who was well-loved and trusted by students and adults, was removed from the school and that Linwood hasn't said why.

In her letter, Linwood stated that "at no time were our children in danger" due to the threat.

But teachers said there was no way for Linwood to know if students were in danger when the threat was made and that it should have been taken more seriously in light of the rash of deadly school shootings that have occurred around the country.

"It should have been handled wisely," Bounds said. "It should have been handled instantly. It was not handled in a prudent manner at all."

The school's corporate office declined to comment on how the notification of parents and school staff was handled.