UPDATE: Diamond Ranch High School Lockdown Lifted

Final update: 

This was the final message posted by the Pomona Unified School District about the lockdown at Diamond Ranch High School: 

The lock down at Diamond Ranch High School has been lifted.  No evidence of danger was found on the campus. Classes will remain in session until 2:20 p.m. as scheduled. Parents who wish to pick their child up prior to end of the school day may do so at the gym. 

Please note that emergency release protocols will be in place, meaning that only those listed on the students emergency release card will be able to pick up students and picture identification will be required.

We thank you for your patience during this incident. We appreciated the commitment of our local law enforcement officers in keeping our students and staff members safe. All after school activities scheduled for today are cancelled and arrangements will be made for finals to be taken when school resumes in January.

Update 1:30 p.m.: 

The Los Angeles Sheriff's Department says that the temporary lockdown at Diamond Ranch High School in Diamond Bar has been lifted.

"Investigation revealed there was no indication the threat was credible," an alert from LASD says.

"School officials and deputies walked the entire campus, including the classrooms, as a precautionary check and to reassure students and staff."

The sheriff's Special Enforcement Bureau (SEB) "went tot he area as a precaution"-- but left soon thereafter when officials determined there presence wasn't needed.

"At this point of the investigation, there is no specific information that the threat is credible," said Lieutenant Chris Blasnek, Walnut / Diamond Bar Sheriff's Station. "Yet we take all threats seriously and will continue to work closely with school administrators to do all we can to ensure the safety of students and teachers." 

A "phone threat" call was made to the school around 8:45 a.m., according to LASD.  

"It was just a general threat to the school," the Walnut sheriff's station told Patch, adding that there was no specifics as to things like guns.

Update 11:30 a.m.: 

Sheriff's Department Spokesman Mike Parker has tweeted out several messages reassuring the public that no threats have been found.

His latest message, sent at 11:25 a.m., indicates that Diamond Bar Sheriff's deputies were walking around the classes at Diamond Ranch, "as [a] precautionary check," and to "reassure students."

What's more, Parker says that the department's Special Enforcement Bureau (SEB) and SWAT team were nearby when the lockdown call was made, so they responded to the scene as well-- but made it into a training exercise.

"LASD SEB SWAT & copter were nearby, heard call, went as precaution & made it training exercise," he tweeted.

Update 11:15 a.m.: 

The school district says the sheriff's department has not found any credible threats at campus, but continue to sweep the area.

"The Los Angeles County Sheriff's responded to the school campus and have found no evidence of any threat thus far," a message from the district reads online.  "However, the Sheriff's have brought up additional resources to aid in sweeping the entire campus and surrounding area."

The school stresses that the "situation remains PRECAUTIONARY at this time."

"Unfortunately many districts throughout the nation this morning have experienced false threats regarding the safety of students," Pomana Unified said.  "Any and all threats will be taken seriously."

Original story as follows:

Diamond Ranch High School, located at 100 Diamond Ranch Drive, was put on lockdown this morning after the Pomona campus reportedly received a threatening phone call from a student.

KTLA reported that the call was made at around 9 a.m.

The Pomona Unified School District has posted the following message on its website:

"The Los Angeles County Sheriff's Department has directed Diamond Ranch High School to be placed in lockdown as a precautionary measure to a matter they are investigating.

"All students are safe in class. Parent's will be notified as soon as the lockdown is lifted."

Lorbeer Middle School also was locked down this morning, with the same statement being posted on the school's website.

But Diamond Ranch and Lorbeer were not the only schools in Southern California dealing with police issues Friday. Increased law enforcement presence was in force at South Pasadena High School as well as La Mirada High School, according to a City News Service report.

According to the report, both schools had received threats over the past week that were being investigated. Though police were unable to verify the threats as credible, there were increased patrols around both campuses Friday.