The white and brown pup had been staked to the ground with a rope and shovel, and likely drowned as the tide slowly rose over its head at Mother's Beach in Marina del Rey, according to authorities.
On Friday, the Los Angeles County Sheriff’s Department said it was investigating the animal's death after its carcass was spotted recently by a group of lightweight boat paddlers.
The group was splashing past Mother’s Beach on Wednesday morning, when they noticed a blue-handled shovel sticking out of the water.
When they got closer to the shovel, they were shocked to find the animal tied to it. A black rope had been wrapped around the dog's neck and the lower portion of the partially submerged shovel.
The paddlers moved the animal up to a dry area of the beach, according to sheriff’s Sgt. Jeff Slutske.
The mixed-breed dog likely drowned as the tide came in, Slutske said. The animal had an identification tag, he said.
One of the paddlers, Malia Zimmerman took a picture of the animal and posted it to her Facebook page.
"Sometimes people can be extraordinarily cruel," she wrote.
Zimmerman also posted a photo of the animal's identification tag. It read: "Dog License Animal Services 1476765"
The Los Angeles County Department of Animal Care and Control is also investigating the incident.
Anyone with information on the incident should call the Sheriff's Department at (310) 482-6000, Slutske said.
For the record
3 p.m., March 19: An earlier version of this article included an incorrect phone number for the Sheriff's Department.
"We already reported this act of animal cruelty but it would be great to catch the puppy killer," Zimmerman wrote.