Since 2010, 71,000 guns were reported lost or stolen in California, according to data obtained by NBC 7 Investigates, more than a dozen NBC stations across the country and the nonprofit journalism organization, The Trace.
Many of those weapons are arming the very criminals they are meant to protect against.
Stolen and lost guns come from many places, including gun dealers, pawn shops, law enforcement. The largest number of them come from private owners. National Crime Information Center statistics show thefts from private owners increased 42% from 2005 to 2014.
Five years ago a San Diego area law enforcement officer, who wished to be identified only as Mike, said he was devastated after his nine-millimeter semi-automatic handgun was stolen from his car.
"Because of me, I put a gun on the street," he said.
According to Mike, he returned home around five o’clock in the morning after his second double shift in a row. Tired, he said he forgot the gun in his console and locked the car. Later that night a thief struck.
“The gun was missing,” Mike said. “My wife she had some Prada glasses in there. The baby's diaper bag was missing. It all hit me.”
In data from more than 1,000 law enforcement agencies in 36 states and Washington D.C., NBC 7 Investigates found more than 204,000 guns stolen since 2010. In San Diego County, nearly 200 stolen guns were recovered in connection with crimes, including two attempted murders, 15 assaults, and 40 burglaries.
ATF Operational Intelligence Agent Kevin O'Keefe said after cash, guns are the most desirable thing to steal.
"We just ask that everybody partner to realize what's going on to not make it easier for the bad guys to get at these guns," he said.
According to the police data, of the thousands of guns lost or stolen from California, 359 traveled more than 50 miles; some traveling as far away as Maryland, New York, and Florida.
Sixteen hours after stealing Mike's weapon the suspect's getaway vehicle was photographed on the South Bay Expressway. According to Mike, the stolen diaper and gym bags in the bed of the truck can be seen in a photo taken while the vehicle traveled through the checkpoint.
Mike’s gun was ultimately recovered and wasn't used in any crimes. A relief to this law enforcement agent who is also a father of three.
"I don't want any danger to come their way and I don't want it to be me to be the cause of that," Mike said.
Mike reported the theft of his gun to the Chula Vista Police Department.
In California, Proposition 63, which went into effect in July, requires gun owners to report stolen weapons within five days or face fines up to one thousand dollars after multiple infractions.
A spokesperson for the National Rifle Association said, "a law that requires reportage (of stolen or lost guns) is nothing but punitive. It does not prevent crimes from being committed, and it only serves to further victimize¦ an otherwise law-abiding person(s) after they've been robbed."
Mike said he now transports his handgun in a firearm safe bolted to his car.
“It's better that the average citizen has weapons and is able to protect them,” Mike said. “With the responsibility that comes with it, you just can't be careless.”
He said he turned one careless fatigued moment into a forever lesson so the next crime he investigates isn't perpetrated with his gun.
The FBI estimates 2 million guns were lost or stolen in the U.S. over the last 10 years. According to law enforcement experts, a quarter of those are never reported to police.