Six seals - some carrying pups - have been found washed up dead on Shetland after apparently being shot.
Three of the common seals were said to have clear exit wounds to the head, and post-mortem examinations showed two female seals were carrying large pups.
The Scottish SPCA, appealing for information, said it feared there may be more seal carcasses washed up in other areas not yet discovered.
The discovery was made at Mara Ness, Bridge of Walls.
The Scottish SPCA's senior inspector Ron Patterson said: "This is a serious wildlife crime and we are therefore very keen to speak to anyone who may have witnessed seals being shot in the area or who may have information relating to the shooting of seals.
"Common seal numbers are decreasing and the illegal shooting of seals is a contributing factor. In fact, it's almost wrong to call these animals common seals because they are gradually becoming a rare sight in the waters around Shetland."
He added: "Shooting a seal at anytime of year is a very cruel and callous act, but June is the time when common seals are actively breeding and having their pups.
"It's not only the adult seals that are killed, but any unborn pups are slowly starved of oxygen and any orphaned newborn pups are sentenced to a lingering death of starvation as they cannot possible survive the early days without their mother's milk.
"It is also likely once the pups are in a weakened state, but still alive, they will be attacked by birds which inevitably means the birds will attack the softest part of their bodies first while still alive."
Anyone with information can contact the Scottish SPCA animal help line on 03000 999 999, the Shetland Wildlife Rescue Unit on 01595 840 321 or Northern Constabulary on 01595 692 110.