Police said Monday that they uncovered a mass-shooting plot at South Pasadena High School, arresting two students on suspicion of planning to "kill three staff members and as many students as possible with firearms."
The two students were arrested after detectives served search warrants at their homes, according to the South Pasadena Police Department.
One of the students resisted arrest, prompting officers to force their way into his home, according to police officials.
"He was captured in the home as he tried to run away," Sgt. Brian Solinsky said in a statement.
He said that school officials became aware of suspicious behavior and contacted law enforcement authorities.
"It was this information that helped prevent a horrific tragedy," Solinsky said.
He did not respond Monday night to a request for comment, but he said in his statement that police would be releasing details on the case at a news conference Tuesday morning.
South Pasadena Unified School District Supt. Geoff Yantz said that school administrators were informed of a "credible threat of potential school violence" and immediately contacted police.
"The police have the situation under control and there is currently no threat to students or employees," Yantz said in a statement.
He said psychologists and counselors will be at the school to support students and employees. Classes start Thursday.
Two school parents said Monday night that they were glad that police acted quickly.