After a caller to 911 reported what they said was "a body" on 101 in San Francisco last night, the California Highway Patrol learned that a collision on the freeway had killed at least one person.

According to a CHP spokesperson, the 911 caller reported that an unknown object, believed to be a human body, was lying in the southbound lanes of 101 just south of Third Street at 10:48 last night.

It was that point that officers realized that there had been a two-vehicle collision in that area, during which "at least one" of the vehicles' occupants had sustained fatal injuries. A call to CHP for more details on the collision was not returned at publication time.

Southbound 101 was closed as emergency crews responded to the scene, and didn't reopen until around 2:03 Tuesday morning, according to the CHP's twitter account.