He added: "It was really cold and rainy, and he’s just sitting out there leaning against a tree.
"The tone of his voice when he was yelling, it was very desperate.”
Tributes have been flooding in for Sara, who also worked as a model and voice-over artist.
One family friend said: "Sara was funny, kind and a great mother. She was the kind of person to give you the shirt off her back."
Another devastated pal added: "Her son, I mean, I don't know if he comprehends that she's never going to come back.
"It takes an evil, evil person to do something like that."
Police said in a statement they would release the suspect's identity "at a later date".