UPDATE 4 P.M. ET: The two children who were injured are now in critical condition, according to CNN.

Local authorities say two people were killed at an elementary school in San Bernardino, California. Two students were also wounded and taken to trauma centers. The active-shooter situation appears to be over, though the school, North Park Elementary, has been evacuated as police investigate.

“We believe this to be a murder-suicide,” San Bernardino Police Chief Jarrod Burguan tweeted. “Happened in a classroom. Two students have been transported to the hospital.”

The two dead adults are believed to be the gunman and a teacher. Officials have indicated that the shooter walked into a classroom and shot the teacher, who may have been a former girlfriend, then turned the gun on himself.

“We do not know the age of the students. We do not know the grade that the teacher taught,” San Bernardino City Unified School District spokeswoman Maria Garcia told reporters.

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