16-year-old stabbed outside Long Island high school, 15-year-old in custody, police say

One teenager was seriously injured in a stabbing outside a Long Island high school Thursday, and another teenager is in police custody, Suffolk County Police say.

It happened around 2 p.m. in the parking lot of Sachem High School East in Farmingville.

According to police, a 16-year-old student was stabbed and taken to a local hospital in serious condition. Police say a 15-year-old is in custody.

In a statement, Sachem Superintendent Patti Trombetta said the stabbing happened during dismissal time, and police said the campus is secure at this time.

"All our thoughts are with the student and his family at this very difficult time," Trombetta wrote, in part. "The health, safety, and welfare of our students remain our highest priority as a District. We understand the great concerns this incident may cause within the Sachem community. The District will proactively work with our own security team and the Suffolk County Police Department to address those concerns."

A motive remains unknown at this time. The investigation is ongoing.

Sachem East, with a student body of 2,000 students, is one of two high schools in the sprawling Sachem Central School District.

Senior Andrew Frederick told CBS News New York he and others can't recall any other recent violence at the high school, which is considered a solid public high school with a strong graduation rate.

"People were very surprised everywhere. It, like, wasn't expected. Like, an average Thursday. The weather wasn't that bad," Frederick said. "It just kind of came out of nowhere."

The 15-year-old is expected to be arraigned Friday as a juvenile offender in the youth section of the criminal court system in Central Islip.

Stay with CBS News New York for the latest on this developing story.