Authorities allege Alfredo Fraga came up behind the 58-year-old woman as she jogged on the trail, then dragged her into the bushes.
It was 2 p.m. Memorial Day on a busy trail in North Tustin.
"I looked 'cause it was just, it was just -- she just kept screaming," said eyewitness "Lis." "And I saw him and he had her in a headlock."
"Lis" and her husband "Jim," who only want to use their first names, were driving by.
"So I just said, 'Jim, turn around, something is not right,'" said Lis.
"I jumped out of the car and told Lis to call 911 and then we knew that our friend, who's an off-duty sheriff, was in town," said Jim. "So I said, 'Go get Scott.'"
Lis picked up off-duty Orange County Sheriff's Deputy Scott Steinle, who happened to be nearby for the holiday, and drove him to the area. The deputy spotted Jim, who was chasing after the 20-year-old suspect. Lis meanwhile stayed on the line with 911.
After a short pursuit, Steinle says he was able to get a hold of Fraga's arm.
"I identified myself and at the time I was able to subdue him and detain him until other deputies arrived," said Deputy Steinle.
The Orange resident now faces numerous charges, including attempted rape, penetration with a foreign object, and kidnapping.
"It's very frightening," said nearby resident Arlene Brown. "We've never had this type of thing here before."
Steinle is grateful people stopped to help.
"The gentleman was quite a large individual and I, I definitely believe without Jim and Lis reacting the way that they did, that this woman probably would have been worse off," said Deputy Steinle.
"I would want someone to do the same for me," said Lis. "So I'm happy to do it. I didn't think twice."
Authorities say that the female victim was taken to a hospital. She did not suffer any major injuries.