UPDATED | February 6, 2017 4:30 PM

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TROPHY CLUB (CBSDFW.COM) It was one week ago when a bomb threat at Byron Nelson High School had teachers and students on lockdown from the afternoon late into the evening. Monday, police in Trophy Club confirm they have made an arrest in the case.

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The person arrested is a juvenile who attends Byron Nelson High School.  The student faces a state jail felony.  Police are investigating a second suspect who they expect to arrest soon.

“The individual we believe is not here in Texas, not a student of Northwest ISD, nor has he ever been.  But we are working with our federal counterparts and our state counterparts to track this individual down,” said Trophy Club Police Chief Patrick Arata.

Police began investigating a bomb threat just before 3 p.m. on Monday, January 30. The message indicated the threatening person was inside the school with a handgun and had planted a number of pipe bombs throughout the school.

Investigators said the person called a total of six times over the next few hours. They said the caller not only enjoyed “taunting the police but mocked the response” by talking about the police officers, SWAT team members and helicopters that were at the school.

The campus was placed on lockdown and police told administrators to keep students in place until they could sweep the building.

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It wasn’t until the last call was placed that the person on the phone stated the entire thing had been a hoax.

“On the sixth call, the individual called in, he was using a voice amplifier so his voice didn’t sound like a normal voice‚ but he at that point indicated that it was a hoax and that he could not believe the response that he received or the fact that we even took him seriously in the first place,” said Chief Arata. 

Everyone was finally permitted to leave Byron Nelson High just after 7 p.m. when the campus was found safe, but a number of vehicles remained at the school overnight while parking lot sweeps continued.

The minor currently in custody has been charged with making a false alarm or report and is believed to be the person who inside the school texting the person making the phone calls, giving them updates on police activity, details about the layout of the school, names of students and locker numbers.

Investigators say the person on the phone was at a different location making the calls.

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