The incident happened at about 3:30 a.m. last Saturday along Burton Way, between South Hamel Road and South Willaman Drive.
Officials said the victim was walking in the area when a man approached and demanded her property at gunpoint. The suspect then forced the victim to a secluded place, where he sexually assaulted her.
He fled with the victim's money and jewelry.
The suspect was described as a black man between the ages of 26 and 35. He's 5 feet, 10 inches to 6 feet, 1 inch tall and weighed around 180 to 190 pounds.
He was wearing a black button-down collared shirt, dark pants and a baseball cap.
The LAPD has posted community alert fliers in the area. Los Angeles resident Tali Delamare said she no longer feels safe walking home from work because of the incident.
"Always thought this was a really safe neighborhood, never worried about it before. It's really shocking," she said.
Anyone with information was asked to call Los Angeles police at (877) LAPD-24-7.