In addition to posting the pooch's disappearance on Twitter, she's also working with professional pet finders FindToto.com, Colleen Busch, the company's director of public relations, tells Usmagazine.com.
"We're kind of an amber alert for missing pets. We took the address of where Daisy went missing and we used that as a bullseye," Busch tells Us. "We called 1,000 neighbors in the surrounding area [Wednesday morning] and sent out a 30-second message with details about Daisy and her disappearance, and details on how to get in touch with Jessica's assistant.
Busch says the company -- which also helped Victoria's Secret model Alessandra Ambrosio find her missing pooch -- "thinks Daisy might be injured. The calls get people on high alert to check their back yard, check under their deck." (Celeb dog trainer Jennifer McCarthy told Us Tuesday she feared the pup, a gift from Nick Lachey, had been eaten.)
Normally, FindToto.com would charge $175 for the service, but they offered to help the singer for free, Busch says.
Simpson, 29, is grateful.
"She emailed us to tell us, 'Thank you.' I think it's been a devastating experience for everyone in her camp," Busch says. "It sounds very upsetting. She was very appreciative and thankful we offered to help."
More on Wonderwall:
More on Usmagazine: