Sea lions poisoned at Pacific Marine Mammal Center in Laguna Beach

LAGUNA BEACH, Calif. -- The search is on for whoever poisoned sea lions being treated at the Pacific Marine Mammal Center in Laguna Beach.

Laguna Beach police say someone poured large amounts of chlorine into a salt water holding pool, injuring sea lions - some of which were ready for release.

More than 400 sea lion pups have been rescued this year alone by Pacific Marine Mammal Center. Most were brought in because they were malnourished and needed to be nursed back to health.

It was the first attack at the nonprofit center in its over 40-year history. Detectives believe the suspect entered the center between 8 p.m. April 27 and 6 a.m. April 28.

The injured sea lions pups are considered evidence in an ongoing criminal investigation

"The injury was what is known as a corneal ulceration of the eye," said Keith Matassa, former director of the Pacific Marine Mammal Center. "It's due to chemicals burning the eyes."

Police are not saying how the suspect broke into the facility, only that they poured a large amount of chlorine into the water filtration system where 17 sea lion pups were already being rehabbed.

"It's hard for all of us. Our volunteers and staff have taken these animals from near death and rehabbed them back and gotten them ready to go back in the wild, and to have this happen right before they're ready for release, it's shaken the staff," Matassa said.

Eight pups have healed, but seven still need continued treatment and will be kept for at least four more weeks

Police are reviewing surveillance video from the property and nearby properties in an effort to identify the suspect and bring him or her to justice.

The Marine Mammal Center has hired a security guard overnight as a result. They do hope these animals will make a full recovery and be able to be release.

The suspect can expect to face animal cruelty charges, which carries a $20,000 fine and a year in prison.

Anyone with information is urged to call Laguna Beach detectives at (949) 497-0377 or the National Oceanic and Atmospheric Administration (NOAA) hotline at (800) 853-1964.