ARF, located in Chester, Md., announced the reward on its Facebook page.
ARF says a couple in their 20s came to the foundation around 4:30 p.m. on Tuesday, Sept. 25 to visit puppies. After a quick visit, the couple left and drove away.
The puppy, Mango, a male Miniature Pinscher/Dachshund mix, was soon discovered missing.
The foundation says the man was approximately 6-feet-tall, had dark hair, a strong body and his left arm was covered in tattoos.
Anyone with information is asked to call ARF at 410-643-8700, or email at firstname.lastname@example.org.
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