Emergency crews are investigating a report that a car is in the Oakland estuary, a fire official said.

A passerby reported seeing a car in the estuary, near Jack London Aquatic Center at 115 Embarcadero West at around 2:30 a.m., fire Battalion Chief Emon Usher said.

The witness reportedly responded to the site and found the vehicle had gone underwater, Usher said.

Responding crews said they saw something red under the water’s surface but could not tell what it was, according to Usher.

The passerby remained on the scene with emergency crews. It was not known if anyone was in the vehicle that allegedly submerged.

The Alameda County Sheriff’s Office’s dive team is expected to arrive at around 6 a.m. to investigate further, Usher said.