The suspect followed the victim down 24th Street from South Van Ness Avenue to Potrero Avenue sometime between 3 a.m. and 4 a.m., police said.
He eventually demanded money from the victim, and when she did not give him any money, he grabbed her and took her to another location nearby. The man then choked, punched, slapped and sexually assaulted the victim before fleeing on foot.
The suspect is described as a 35- to 50-year-old black man with a medium to light complexion standing between 5 feet 11 inches and 6 feet 1 inch tall. He has a round, clean-shaven face, large eyes, a round nose and thick lips, police said.
He was last seen wearing athletic apparel including a light gray hoodie with a front zipper, blue cotton running pants and tennis shoes, possibly in shades of black and white, according to police.
Anyone with information about the case is encouraged to call the Police Department's anonymous tip lin