NEW YORK -- A photograph of four people carrying what looked like assault rifles sent law enforcement scrambling in New York City on Friday.
It turned out they were paintball guns -- very realistic-looking paintball guns.
The photos show men and a woman carrying what looks like some serious weaponry at a Staten Island parking lot. A retired police officer snapped the images, and the response was massive, with checkpoints and searched cars.
The Friday evening rush came to a standstill. Fort Wadsworth was locked down for a couple hours.
The NYPD sent out a "be on the lookout" alert for "individuals armed with what appear to be assault rifles." Investigators acknowledged they might be paintball guns.
"If it turned out to be a terrorist act and these people were going to cause some tremendous damage, we wanted to try and stop them," said Staten Island private investigator Mike Gaynor, who spent years as an NYPD homicide detective.
"These weapons all look so similar or different in certain ways," Gaynor told CBS News. "From a photograph, you're not going to be able to tell for sure."
This photo shows an M-16 on the top and a paintball marker, as it's officially known, on the bottom.
BB guns, water guns, toy guns, even iPhone cases -- the look-alikes sometimes spark deadly consequences.
In November 2014, 12-year-old Tamir Rice played with a pellet gun in a Cleveland, Ohio, park. A police officer shoots and kills the boy.
In August 2014, it happened in Beavercreek, Ohio. A shopper handles a BB gun for sale at a Walmart, and someone calls police. Responding officers shoot and kill the shopper, John Crawford III.
"It's a tremendous burden on the officers today," Gaynor said. "It puts them in a position where they have to think twice, three times before taking action sometimes."
Federal law bans manufacturers from making realistic-looking toy guns unless they include an orange barrel plug. The paintball industry urges its players to disassemble their devices and carry them in bags because of the potential for confusion with real weapons.