According to sheriff's officials, at about 8:30 a.m. Wednesday, the victim was jogging and pushing her 2-year-old child in a stroller along a path near Lake Shore Park when a man -- who was armed with a knife -- jumped out from some bushes, attacked the woman and then sexually assaulted her.
The man ran away following the attack, sheriff's officials said.
Residents said they heard the sheriff's helicopter searching the area but they could not make out what was being said.
"It was very frustrating because also shortly afterwards, I saw someone riding a bike down the street, but I didn't know if that was a suspect or what," said resident Lis Phillips.
Neighbors say there is almost always someone walking or jogging along the trails, especially in the morning.
"It's shocking, I can't believe that happened," said neighbor Kari Taylor.
Lynette Morales and her daughter go there for the privacy.
"So no one can see us running," said Morales.
The sheriff's department has extra deputies patrolling the area until further notice.
It is unclear if the victim will be able to help investigators with a composite sketch.
The suspected attacker was described as Caucasian or possibly Hispanic, 6 feet 1 inches to 6 feet 2 inches tall, with a tanned complexion and dark brown or black hair that is close-cropped. The man may be in his mid-30s to 40 years old, with a heavy "beer-belly" build and a neatly trimmed full beard and mustache.
At the time of the attack, he was wearing a black short-sleeve T-shirt with holes and black work pants.
Anyone with information on this incident is urged to contact the San Diego County Sheriff's Department or Crime Stoppers at 888-580-8477.
A $1,000 reward is being offered to anyone with information that leads to an arrest in the case.