By Herman Wong
It was the smell and sound that caught their attention.
"There was a strong smell of decay, and that in our business is a bad thing," Montclair police Sergeant John Minook told The Washington Post. "And you could hear what sounded like animals moving in the inside of the business."
He and other officers were at an industrial park in the California city investigating the residence of a man who had been arrested for a warrant from another county.
They entered the building and came upon up to 10 cages filled with birds.
As they made their way in, Sergeant Minook saw debris everywhere. Then the trash. And the live animals living in faeces, the sounds of their movements all about.
"Little chicks hopping around - you had to watch that you didn't step on them. It was pretty bad," he said.
They noticed things moving around in containers holding liquids and suddenly realised that there were fish inside. Then there were the dead animals.
"I saw hundreds on the floor. They range from chickens, snake, mice, rabbits, a couple chameleons."
They would find more than a thousand animals - chickens, fish, birds and reptiles, according to the Associated Press.
It was like a Noah's Ark of death.
"This is probably the worst I've seen in my career," Sergeant Minook, who has been on the force since 2010, told the Los Angeles Times.
On Friday, public works employees and The Inland Valley Humane Society & SPCA came to clear out the building. The humane society posted a photo to Facebook, showing cardboard boxes leaning against walls and chickens and birds roaming on trash that completely obscured the ground.
James Edward, operations manager for the local humane society, told the AP that conditions were deplorable, with fish swimming in tanks so dirty that he couldn't identify them. And the smell of ammonia pervaded the building.
"It was definitely uninhabitable for animals or people," Edward said.
The humane society said the birds were in their care and being evaluated. Minook said the non-profit has been tasked with gathering information on the number of animals and determining cases of animal cruelty. The findings would be forwarded to the district attorney's office, who will decide on charges.
Police did not release the arrested man's name, and authorities didn't know why the animals were kept in the building, according to the Associated Press.
The Inland Valley Humane Society did not immediately respond to requests for comment.
Peggy King, who works for another business in the industrial park, told local ABC-affiliate KABC that the situation was "sad".
"For people to be like this, I just don't even comprehend it. Because, really, what are you doing with all those animals?"