In the early hours of Friday morning, police officers in Texas took what is thought to have been unprecedented action for US law enforcement. Using a bomb disposal robot, they killed the suspect in last night's shooting in Dallas after negotiations with the individual broke down. "We saw no other option but to use our bomb robot and place a device on its extension for it to detonate where the suspect was," Dallas police chief David Brown told reporters. "Other options would have exposed our officers to great danger. The suspect is deceased as a result of detonating the bomb."

Many experts believe this is the first time that a bomb disposal robot has been used in this way on US soil. Such robots are controlled remotely, and used for tasks such as surveillance and investigating suspect bombs. Some are equipped with two way intercoms and even cameras to allow for police to negotiate with suspects without risk. When deployed for bomb disposal, they often use small explosives in order to trigger the larger bomb.

But while their intended function is not to injure enemy combatants (or criminals), this isn't the first time they've been put to this use. Peter W. Singer, an expert in military technology and think tank strategist, tweeted that US troops in Iraq had used their own bomb disposal robots in this way.

Singer describes this practice — which used a cheap bomb disposal robot called the MARCbot — in an essay in the book The Changing Character of War:

"The MARCbot is not just notable for its small size; it was the first ground robot to draw blood in Iraq. One unit of US soldiers jury-rigged their MARCbots to carry Claymore anti-personnel mines. If they thought an insurgent was hiding in an alley, they would send a MARCbot down first, and if they found someone waiting in ambush, take him out with the Claymore. Of course, each insurgent killed in this fashion meant $5,000 worth of blown-up robot parts, but so far the army has not billed the soldiers."

Kelsey Atherton, a writer for Popular Science who specializes in defense technology, tweeted that he too thought this was a first for US law enforcement. He pointed out that "the whole point of having robots is to do things that we cannot safely ask willing humans to do," and that although this was an "extraordinary use" for the robot, last night was an "extraordinary case."

An important thing to stress is that the robot was completely under human control. Bomb disposal bots are not autonomous — they rely on human decisions and human controllers, and as such, have quite a long history. Atherton later tweeted pictures of remote-controlled demolition vehicles used by the Nazis in World War II.

These were radio-controlled, equipped with miniature tank treads, and used for tasks like blowing up enemy tanks. The bomb disposal bot used by the Dallas police may have been more technologically sophisticated than these decades-old robots, but its end purpose was just as straightforward.

Bomb disposal robots, though, have emerged as a flexible tool for law enforcement, particularly SWAT teams. In April, members of the California Highway Patrol used a bomb disposal robot to deliver a pizza to a suspect, effectively ending a standoff. And in 2013, a SWAT team in Albuquerque used their bot to remove the blanket from a suicidal individual barricaded in his room, checking whether or not he was armed. (No weapon was found and a SWAT team took him into custody.)

It's not yet clear what robot was used by the Dallas police, but it's been suggested that it too is likely to be a MARCbot, many of which have found their way into the hands of law enforcement via military surplus programs.

Outside of the ethical questions facing the Dallas police department (what led them to take the decision to simply kill the suspect rather than try other options to capture them?), this incident raises a number of practical considerations. These include the decreased usefulness of such robots as negotiators. If suspects fear them as potential assassins, why bother to talk to the police at the other end?

There's also the issue of safety and control. How secure was the communication line between the robot and its controller? Was there a chance of the bomb exploding prematurely or by accident? And how can a negotiator know that negotiation is pointless if they're not physically in the room with a suspect? Should that be a concern in situations when there is a danger posed to the general public?

There will be many more questions than these as details emerge about last night and this morning's events. And while this is not the start of "killer robots" taking human lives, it is another example of governments using technology to exert lethal force at a distance. This is a debate we've started with military drones and their use in foreign countries. Now, the conversation is domestic as well.