A bomb threat at St. Francis High School in Mountain View Tuesday afternoon, Oct. 5, ended up being a false alarm, with a multi-hour search of the campus turning up no explosive devices.

Presentation High School in San Jose also received an unfounded bomb threat Tuesday, which came from the same phone number that was used to call St. Francis, the San Jose Police Department said on social media.

The bomb threats came after Los Altos High School was evacuated on Friday, Oct. 1, due to someone calling the school claiming there were explosives on campus. No bombs were discovered at that high school either.

The Mountain View Police Department released a statement shortly before 6 p.m. Tuesday saying that the threat to St. Francis had been deemed to be "not credible" and an investigation is underway into who made the call.

Earlier Tuesday afternoon, police department spokesperson Katie Nelson said it was unknown whether the bomb threat at St. Francis was connected to Friday's events at Los Altos High.

"Right now we're just trying to take care of St. Francis," Nelson said. "I'm sure we'll learn more in the subsequent hours or days."

Everyone on campus at St. Francis was forced to evacuate after the school received "multiple calls" shortly before 1 p.m. claiming there was an "incendiary device" on campus, according to a press release from St. Francis.

Because school administrators couldn't guarantee the safety of those on campus, they decided to evacuate students and staff to Cuesta Park, St. Francis President Jason Curtis said in an interview Wednesday morning.

"In this case, we felt that we could not keep (students) on campus," Curtis said. "That's a really serious and important decision and I think it reflects our very deep concern about the threat that we received."

Parents were told to pick their kids up from the park, which is adjacent to the school's campus. At 3:15 p.m., Mountain View Police reported that all students were safe and had been connected with their parents.

"Officers immediately began a search of the campus, and called in additional resources to help ensure that the area was safe," the police department said in its press release. "The search lasted several hours, but ultimately it was determined that there was no threat to the campus."

The campus reopened by 5:30 p.m. Curtis praised the efforts of emergency responders, who he said did a thorough search of the campus that took over four hours. Law enforcement is now investigating the source of the threats and Curtis said he couldn't release additional information.

"When anybody is imposing a potential threat to our students, we take that very seriously," Curtis said.

Mountain View High School's administration notified parents Tuesday about the threat to St. Francis, according to an email that a parent shared with this news organization.

"While they are a few miles away, we wanted you to be aware of this local incident as the threats have been occurring within our community in the last few days," the email said.

Students were evacuated at Mountain View and Los Altos high schools on Tuesday after fire alarms went off on both campuses, Superintendent Nellie Meyer confirmed in a text message. The cause in each case was determined to be vaping in a restroom, Meyer said.

Classes resumed at St. Francis on Wednesday and the private Catholic school had counselors and ministers on site to support students and staff. According to Curtis, the school made an announcement during the first period of the day about the available resources and prayed with students.

"We're here for students and for educators throughout the day," Curtis said.

Although he said Tuesday's bomb threat was disturbing, Curtis added that he's been touched to receive emails from students checking in on how teachers and administrators are doing.

"Even in a difficult moment, I think you have those moments of grace, where people really show how wonderful they are and how much they care for each other," Curtis said.