With hundreds of surveillance cameras on city streets, in the air and on officers' bodies, 21st century police departments are relying on technology to fight crime more than ever before.
And one tool in particular is exploding in popularity: robots.
In the first six months of 2016, 201 robots were transferred from the US military to police forces around the country, according to a study by Bard College's Center for the Study of the Drone
. That's more than any other year on record, and doesn't even account for the number of robots acquired by police straight from manufacturers.
Many experts point to the period just after 9/11 as the turning point for robotics entering police work.
According to Peter W. Singer, a senior fellow at the non-partisan think tank New America, it was the military's successful use of robots to disarm explosives in Iraq and Afghanistan that piqued the interest of law enforcement.
Between 2003 and May 2016, the Center for the Study of the Drone found that 987 robots were transferred from the military to law enforcement agencies across the country. California police have received the most, followed by Ohio, Alabama, Virginia and Arizona. But those figures don't include robots purchased by individual agencies, and the actual number in use is likely higher.
So why use these machines at all? The answer varies, but one thing is becoming increasingly clear: The technology isn't likely to help solve some of modern policing's biggest issues.
What kind of robots are police using?
July 7, 2016, will be remembered as the day five Dallas officers were killed in the deadliest attack on police since September 11, 2001.
That's also the date when, for the first time, a suspect was intentionally neutralized by a police robot. After the gunman in the Dallas attack barricaded himself inside a parking garage, police sent in a robot armed with an explosive device, which killed the gunman.
However, police robots aren't specifically designed to deliver lethal force. Dan Gettinger, co-director of Bard College's Center for the Study of the Drone, says robots vary in size and price and are mostly used for two things: gathering intel and bomb disposal.
Among the most popular reconnaissance robots is the Throwbot -- a dumbbell-shaped bot that can be thrown into situations too dangerous for humans and can transmit audio and video back to the operator. Other models equipped for surveillance and bomb disposal are the PackBot -- a small, nimble robot that can be equipped with a variety of sensors -- and the much larger Remotec ANDROS Mark V-A1, which weighs 790 pounds and was reportedly used to deliver the deadly charge in Dallas.
What about lethal force?
For Thor Eells, a 30-year law enforcement veteran and the chairman of the National Tactical Officers Association, the benefits of adding robots to a police force are clear. A commander with the Colorado Springs Police Department, Eells' teams began using the technology over a decade ago since robots can be deployed in dangerous situations and serve as a commander's eyes and ears.
"I'm getting (information in) real time ... and then through that I can make a more informed, complete decision," Eells said.
But there is a downside: The question of when, where and how to use lethal force is just as thorny and sensitive when it's a robot carrying out the act as when it's a human -- if not more so.
"If we don't figure out the policy as a nation ... we're going to be leaving it to each little police department on its own to wrestle with these issues," Singer said. "And just like what's happened in other areas, some are going to do it well, and some are going to do it really poorly."
Eells agrees that in order for police work to really progress, innovative tools aren't enough.
"In the United States, there are over 18,000 law enforcement agencies and there is no, or little, consistency," Eells said. "(That's) the challenge in American law enforcement, and it's with regard to all police equipment and police use of force policies."
What's coming next?
So is a "RoboCop"-style officer ever a possibility on American streets?
"RoboCop in terms of some walking cyborg that mixes man and machine ... yeah, we're not there," Singer said. "We are, however, in a world where robotics are becoming more and more commonplace, and being used by a wide range of actors, from the military to farmers to journalists to the police."
Eells would like to see the technology continue to improve, and as it does, he expects robots to play an even greater role in police work.
"The greatest challenge is to try and find that type of tool that never gets stuck, never breaks down, and isn't limited by battery life," Eells said.
Dan Gettinger sees potential growth in the market for "security robots," which would patrol intersections and scan for suspicious activity in malls and similar environments and wouldn't need to be as rugged as the military kind.
A few companies actually are producing robots for this purpose, but don't expect to see them deployed with any regularity just yet: One such model recently showed a glitch as it ran over a toddler's foot at a California mall