The 37-year-old tested positive for a banned substance last year at a race in Mexico.
She's making her debut there.
American Mary Akor was the women's champion.
Increased prize money has lured some of the best in the sport.
Mary Akor of the United States took third in the women's event.
Peter Magill, 51 years old, runs 1:10:19 to finish fourth overall at Rock 'n' Roll L.A.
Mary Akor won the women's title.
Ethiopia prevailed in the final kilometer.
The 2010 U.S. marathon champion was using the race in preparation for April's Boston Marathon.
A sold-out field of more than 8,000 enjoyed the 34th edition in San Diego.