The foot was discovered around 3 a.m., BART spokesman Jim Allison told SFGate.

Officials believe the foot belongs to a woman who was struck by a train on Dec. 20. She survived the accident but lost part of her right leg.

"This was a right foot," Allison told the Los Angeles Times. "All signs point to the fact that this is probably the same foot."

Authorities told UC Berkeley's The Daily Californian the foot was found near a wall behind the track three weeks after the collision despite an "expansive search and cleanup."