ROCHESTER, N.Y. (AP) — A civil investigation has been launched to determine how an autistic teen was able to walk away from his school and apparently drown, New York state officials said on Monday.

Attorney General Eric Schneiderman and Education Commissioner MaryEllen Elia said the probe into Trevyan Rowe's death will include a review of the school district's policies and procedures to determine what needs to be done to ensure the safety of all students moving forward.

The 14-year-old Rowe went missing in Rochester on March 8 after getting off a school bus. His body was pulled from the Genesee River after a three-day search.

A school district official said five school staff members were assigned to usher students from their buses into the school, but no one noticed when the teen got off the bus around 7:30 a.m. and walked in the opposite direction.

Three school employees marked him as present in school, and his family was not notified that he was gone for several hours.

Soon after he left the school, several motorists called 911 to report someone walking on a bridge over the river, which authorities believe was Trevyan.

City officials said dispatchers failed to follow protocol and send water rescue crews.

Several school and 911 center employees have been suspended.

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