The animal service department received a call Sunday night from a citizen reporting that there were cows in the area that were dying from lack of water, Gamez said.
The problem had been reported to the naval weapons station at about 10 a.m. Sunday and the rancher who owned the cows had rushed to try to save them.
By the time the county animal services officials got there, the rancher had already begun giving the cows electrolytes and was trying to re-hydrate them, but it was too late for some.
Seven cows had already died by Sunday night, Gamez said.
Investigators now believe that a trespasser might have accidentally turned off the water supply to the cows.
The spigot that supplies their water is about 700 feet from their trough and is not clearly marked, Gamez said.
Investigators believe that someone may have turned on a different part of the spigot and then accidentally turned off the wrong valve, shutting off water to the cows without even knowing it, Gamez said.
"It appears to be an accident," Gamez said.
The rancher had recently moved the cows to that area because the fire department was doing a controlled burn near their regular pasture. The pasture they were in Sunday is the only place where the cows have only a single water source, Gamez said.
Investigators have never had any problems with the owner of the cows before and do not believe any criminal negligence on his part led to the deaths of his cattle.
All of the cows that died were breeding cows and Gamez estimated that the financial loss to the rancher could be as much as several hundred thousand dollars.