Staples High School was dismissed early out of "an abundance of caution" after a student had thoughts to execute a mass shooting, police said during a press conference on Tuesday.

The high school in Westport was dismissed at 1:15 p.m. after students and staff were asked to shelter in place. Afterschool activities were also canceled.

Police said they received a call from Staples High School officials at 9 a.m. on Tuesday saying a student was overheard making threats that he was going to shoot a teacher.

When police arrived to the school, the teen was being interviewed by administrators. The school officials told police that the student expressed that he had "thoughts" of executing a mass shooting at Staples High School, according to Westport police.

Investigators are looking into whether those thoughts manifested into an actual plan. Detectives found that there were firearms at the student's home. The weapons belong to the student's father and were reportedly locked in a safe, but investigators could not confirm if all firearms were accounted for, police said.

Officers from Connecticut State Police, Norwalk and Fairfield were sent to Westport police with the early dismissal. Officers were placed at all Westport schools out of precaution until dismissal.

The student is in custody and is being evaluated a medical facility. The investigation is ongoing.

Staples High School will be open on Wednesday and students can expect to see added police units on campus.