In one of my recent Facebook posts, people have begun debating whether the Hunter could be considered a serial killer because of how many people he’s killed. That, of course, led to some fun exchanges about the differences between serial killers and assassins—of which there are a notable few.

Let’s be clear: assassins and serial killers both murder people. Multiple people. In that, they find common ground.

But there are three pretty important distinctions that set the two apart:

Motivation – Serial killers are usually in one of four categories: visionary (psychotic breaks leading them to believe they have a “divine” or “higher” calling), mission-oriented (justifying their actions as being driven by a purpose or moral cause), hedonistic (killing for the “thrill” of it, often psychosexual gratification), and power or control (exerting power over their victims, typically because they felt power or control taken away from them, particularly during abusive childhoods).

Assassins, hitmen, and contract killers, kill because they’ve been hired to do so. They often don’t directly know either party (client or target) and carry out the kill with methodical detachment. Assassins may have serial killer traits, but aren’t classified as serial killers because there is a monetary incentive and typically a lack of emotional motivation.

Victimology – Serial killers choose their own targets, usually for a specific reason (depending on which category they fall into). Assassins, however, don’t. They take on the task of killing their targets due to someone else’s desires. For them, there is no personal motive to execute the assassination; they’re simply being paid to do so.

Cooling Off Period – Serial killers typically experience an emotional “cooling off period” between kills. During this period, they’ll blend into their lives once again, acting as if everything is normal. This period may last for hours, days, months, or years. During this time, they’ll feel a growing urge to kill until they finally succumb again.

Assassins, however, have no need for a cooling off period because there is no emotional investment in the kill. They are unemotional and pragmatic, carrying out the kills methodically. They can go from one kill to another without delay because of their detachment from the target.

There are plenty of arguments to be made about methodology, professionalism, means of choosing targets and setting up the kills, and so on. But at the end of the day, it’s these three differences that are most noticeable between serial killers vs. assassins.