When they got inside July 2, they found only one thing burning: a 41-year-old man who became engulfed in flames and died after cutting through a high-voltage line.
Sean Phelps became another ghastly casualty of what authorities say is a deadly national trend: copper wiring thefts.
High copper prices in recent years have thieves breaking into power plants and abandoned factories to rip out the wiring. Vandals are even stealing from gravesites.
There is no national count of people killed in copper theft attempts, but news accounts put the death toll at about two dozen over the past 12 months.
Mr. Phelps, a father of nine and a former long-haul trucker who family members say was trying to scavenge scrap metal to help support his family, was found alone in the empty building, next to a set of bolt cutters, a police scanner and the store's lone remaining electrical panel. He wrongly assumed the power would be off, authorities say.
When Mr. Phelps cut the wire carrying at least 220 volts, he was hit with a powerful electrical arc, similar to what happens when lightning strikes or a transformer blows.
Most copper thefts are nuisances, such as a recent rash at a Maryland youth baseball park that has left Little Leaguers without lights for night games.
But increasingly, thieves are turning to the highest-quality sources of copper - power substations, utility poles and electrical boxes - and turning over the easy-to-recycle wiring to scrap dealers.
The practice is so dangerous that utility workers refer to it as "a dance with the devil." But it is profitable for those who don't get hurt.
Copper prices have shot up almost fourfold in the past decade, an increase attributed to rising demand from Asia. Copper now trades on financial markets for $3.65 a pound. The metal is hard to trace and retains its value well when recycled, so thieves are even targeting copper alloys such as brass.
Pipes and air conditioners have been stripped from homes and churches. California farmers have had irrigation machinery plucked. In Guam, 34 brass panels on a World War II memorial were stripped earlier this month. Thieves last year stole $10,000 worth of brass toilet flush valves from parks in Honolulu.
Police in Maryland, Ohio and Wisconsin say copper urns or brass plates have vanished from cemeteries.
"They don't realize how much danger they're putting themselves in for $3 a pound," said Betty Kennedy, a spokeswoman for Atlantic City Electric in New Jersey, where a man was hospitalized last month with severe burns on his arms after police say he tried to steal copper wire from a substation in Millville, N.J.
In Ohio, a man was electrocuted Monday when he tried to take down a power line to sell the copper. Sheriff's deputies found the man tangled in the line, and utility workers had to remove the body.
The copper theft spree prompted 20 states to pass laws this year to curb the problem. Much of the attention has gone to metal recyclers, who in many places could buy scrap without asking where it came from.