By Sharon Bernstein

SACRAMENTO, Calif. (Reuters) - Authorities in California are trying to determine why someone has been dropping bags filled with the bodies of decapitated animals near railroad tracks in the capital city of Sacramento.

On Monday, the city released a surveillance video of what appeared to be a woman dropping off the headless carcass of a goat, along with a similarly mutilated rat and catfish, and a bag of decapitated red hens, said Gina Knepp, spokeswoman for the Sacramento Department of Animal Control.

"It's bizarre," Knepp said. "We don't know if it's religion; we don't know if we have a sick individual in our community that simply likes to cut the heads off animals and dump them where people can see them."

Since the beginning of the year, more than a dozen sets of remains have been found in Sacramento, some of them in plastic bags placed near railroad tracks.

Past incidents involved goats, roosters and a tortoise. Some have also involved oil, seeds that are used in some Afro-Caribbean religions and dollar bills covered in blood, she said.

In the video, someone police say appears to be a woman parks a white van on 26th Street in Sacramento and gets out, struggling under the weight of an object that she carries around the side of a yellow wall.

Police are hoping to find the woman and talk to her, Knepp said.

(Reporting by Sharon Bernstein; Editing by Ken Wills)