Rodriguez, who had trained the dog and its handler, said he was told that when the air conditioner failed, so did the heat alarm, which is designed to set off a siren and roll down the vehicle's windows when the temperature inside rises too high.
The dog, Serge, was found by his handler outside police headquarters in downtown Camden around 12:30 p.m. Thursday after what a police statement said was a "malfunction" in the vehicle's air-conditioning system.
The outdoor temperature in the area reached a high of 92 degrees shortly before 3 p.m. that day, according to the National Weather Service.
Police Chief Scott Thomson acknowledged that the heat alarm specially installed in the K-9 vehicle, a 2008 Ford Crown Victoria, did not alert the officer but declined to say what role that played in the death of the animal.
"Specifics of the case are currently being gathered as part of the investigative process along with an assessment of all the vehicle's mechanical systems," Thomson said in an e-mail. "We still have much more investigating to do before we determine causes and issue conclusions."
In the summer, when temperatures across much of the country routinely breach 90 degrees, the death of police dogs from heat exhaustion is an annual if not more frequent occurrence, said Russell Hess, national director of the U.S. Police Canine Association.
Sometimes it's due to being overworked while out on duty, but more often than not the deaths occur with dogs left in vehicles.
"It has been a problem with some law enforcement due to malfunctioning equipment, some of it due to human error," he said. "We usually hear about it every summer."
In 2009 a Mount Holly police officer and her husband were charged with cruelty to animals following the death of a police dog left in their vehicle for two hours in mid-July. The officer, against whom charges were later dropped, maintained she left the engine and air conditioner running with the expectation her husband would pick up the vehicle. Her husband later agreed to a plea deal.
Leaving police dogs in vehicles with their engines and air conditioners running is an accepted practice that helps the dogs, with their thick fur coats, cool down after working outside, Rodriguez said.
Rodriguez, who trains K-9 officers from all over New Jersey, said he recommends that handlers check their dogs every 20 minutes but admitted with the frenetic nature of police work and increasing reliance on heat alarms that often does not happen.
He was skeptical of the heat alarms, which he said had been known to fail.
"They're like anything else. They can be hit or miss," he said. "You get a false sense of security."
Heat alarms, which are designed to prevent the death of canines - the animals cost police departments around $10,000 - have been in production for at least three decades.
The heat alarms in use by Camden police were manufactured by Ray Allen K-9 of Colorado Springs, Colo., according to Thomson.
Matt Akenhead, vice president of sales for the company, said he had not yet been contacted by Camden police, but added that oftentimes when a heat alarm fails it is because of an error in connecting the equipment to the vehicle's electrical system.
"Our system is made to be the last line of defense, but there is a specific installation process that needs to be followed," he said.
The death of Serge has struck a chord in the world of K-9 officers, who not only work with the dogs but bring them home at the end of their shifts.
Serge, a less-than-two-year-old German shepherd, joined the Camden police force in January and was sent off to four months of training in Egg Harbor with his handler, Officer Gabriel Rodriguez (not related to Joe Rodriguez).
Joe Rodriguez, who trained the pair and himself was a K-9 officer in Atlantic City for years, said he had tried calling his former student but had not yet heard back.
"I'm sure he's an emotional wreck," he said. "It's not just a pet. You rely on these dogs, especially in the cities, where you're dealing with violent situations."
Contact James Osborne at 856-779-3876 or firstname.lastname@example.org, or follow on Twitter @osborneja.