The 43-year-old homeless woman, known as Janna, was found beaten on Dec. 2.
Police said she received facial injuries and bone fractures, and remains in hospital in critical condition.
"She is a mom ... she's very simple, very uncomplicated," said Surrey Urban Mission's Jonquil Hallgate, adding she's seen the woman in and out of the shelter for several years.
"Here's a woman in our community brutally assaulted and left for dead and nobody cares enough to mention it happened."
Surrey RCMP, reached Tuesday, said they couldn't rule out the assault as a random attack. However, they said no warnings were released because the "greater public" wasn't at risk.
"We've already spoken with several witnesses and we continue to do so. We're still looking to identify the suspect," said Cpl. Bert Paquet.
Police have spoken with Janna's family.
Hallgate said a witness told her the woman appeared to have been chained to a tree, sexually assaulted, and beaten. She also had one of her eyes badly scratched.
She was found by a secluded field behind businesses just after noon that day.
Investigators are looking for more information from anyone who saw what happened before police arrived.
"It is an area that is known to us for drug-related activities as well as some transient persons living or hanging out in that area," Paquet said.