Locals in Letterkenny have been warned to be on the lookout for people in a white Transit van taking pictures of pet dogs in the area.
A warning message has been posted on the Lurgybrack Community Text Alert scheme.
The incident happened in the Knockbrack area in recent days.
When spotted the person said the van took off at speed.
Another poster said a similar incident took place in the Drumany area recently.
There are fears the dogs are being stolen to order.
Anybody who notices anybody acting suspiciously is asked to contact Gardai.