Action for Animals Humane Society in Derry Township says a half dozen people asked about the free dogs last week. Shelter officials have turned the matter over to police, who haven't determined who placed the ads.
The scam included information about e-mail inquiries and people who used it received a follow-up e-mail requesting a $45 donation.
The no-kill shelter about 40 miles east of Pittsburgh doesn't offer animals for free or in return for donations. It charges a $120 fee for dogs and $70 for cats, which helps pay for spaying, neutering, vaccinations and an identification microchip.