A gunman is still at large after opening fire at a high school in Parkland, Florida, killing at least one student and injuring more than 20 others. The school has been placed on a lockdown as police continue to search for the suspect.

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A gunman killed at least one person and injured over 20 others at a high school in Parkland, Florida on Wednesday. The suspect has reportedly been apprehended. Authorities believe he was a former student at the school.

Law enforcement officials say about 20 people were injured in the incident, which took place at Stoneman Douglas High School, located about 50 miles north of Miami. They believe the death toll may rise considerably.

The school has been placed on a lockdown. Some students have posted photos of their situation on social media. The Coral Springs Police Department tweeted that those in touch with students should remain “calm and barricaded” and refrain from calling 911.

This is a developing story. Check back for updates.