Last week, the FBI and Michigan law enforcement agents arrested 13 men on charges that they had plotted to kidnap Michigan Gov. Gretchen Whitmer (D). The FBI tracked the alleged conspirators, many of whom are affiliated with the anti-government Wolverine Watchmen militia, for seven months.

My research on kidnapping by armed groups can illuminate the dynamics behind these events. Here are five things to know about kidnapping by armed groups.

Kidnappers rely on division of labor

Kidnappings require a lot of effort to plan and carry out. In dozens of interviews I conducted with former Colombian rebels, they laid out what was involved in identifying a target and successfully executing the “take,” their term for the moment of abduction.

For example, a former rebel from the Revolutionary Armed Forces of Colombia (FARC) told me that everyone involved in a kidnapping has a special role, saying, “There’s someone good at driving, someone good at talking on the phone, someone to help with injuries. It was my job to guard the take. Everyone has his function.”

Similarly, official al-Qaeda documents describe five separate roles crucial to kidnappings: early surveillance, operational security, abduction, guarding the hostage during captivity and “blocking the chase.”

We saw at least three of these defined in the government’s criminal complaint about the foiled Michigan plot, which alleged that the group surveilled the governor’s house, met in underground hideouts for security, and planned to blow up a bridge to prevent police from pursuing them.

Kidnappers prepare — and that can get them in trouble

A former Colombian rebel from the National Liberation Army (ELN) explained: “We find out [our potential hostage’s] routine, what time they leave the house, where they live. On the day of the strike, we don’t leave anything to chance.” Former kidnappers explain that this planning can take six months to a year.

Law enforcement officials rely on this careful preparation. Conspiracy to kidnap becomes a felony only when someone takes concrete steps toward carrying out the crime.

Though the Michigan suspects allegedly discussed kidnapping the governor and killing law enforcement officers for months, it was only when they actually began surveilling Whitmer’s vacation home in August and September and bought explosives in October that the FBI could charge and arrest them, authorities said.

Operational security is key

Because kidnappings unfold over a long period of time, armed groups generally invest a significant amount of energy and resources to keep their plans and identities secret. Moreover, holding a hostage captive risks inviting rescue missions — a priority of U.S. and foreign special forces.

To prevent monitoring, the Michigan suspects met in a basement accessed through a trap door, used messaging encryption services, and didn’t bring their cellphones into meetings, authorities allege. But they didn’t know that at least two of their co-conspirators were confidential informants for the FBI, or that two others were undercover federal agents.

The Michigan suspects considered two kinds of hostage taking

Over six months of scheming, the Michigan suspects allegedly considered two very different types of hostage-taking attacks. Their original plan, described in June, was allegedly to recruit 200 men to storm the Michigan Capitol building, take the governor and others hostage, and “try the governor of Michigan for ‘treason.’ ” In such “barrier-siege” hostage takings, perpetrators take over a location and hold hostage everyone inside.

By July, however, the men had allegedly decided to snatch Whitmer from her vacation home and bring her to a “secure location” in Wisconsin for “trial.” That makes it an example of a kidnapping, in which a hostage is abducted and subsequently held in a new location.

This change of plans mirrors the evolution of hostage-taking over the past 50 years. In the 1970s and ’80s, kidnappers had a choice. They could commit barrier-siege attacks to demand — and win — media attention. But these attacks were risky for the kidnappers themselves, bringing confrontations with military or police. Or they could bring hostages to secret locations and hope to extract concessions — giving up media attention but increasing their odds of survival.

That’s changed, thanks to modern technology. For the past two decades, kidnappers have been able to move to a secret location and still broadcast their demands. They no longer need to choose between publicity and their own safety.

The Michigan suspects could have broadcast their “trial” from their secure location, gaining extraordinary attention. Ironically, by allegedly planning to bring the governor to Wisconsin — crossing state lines — they made their plot a federal crime.

Famous hostages face spectacular violence

What might have happened had Whitmer been kidnapped and tried for treason? The historical record is dark.

In 1978, the Red Brigades, left-wing Italian terrorists, kidnapped former prime minister Aldo Moro, put him on “trial” and sentenced him to death. When the Italian government refused the terrorists’ demands to release 13 of their imprisoned comrades, the Red Brigades killed Moro and left his bullet-riddled body in the center of Rome.

Twenty years later, the FARC kidnapped then-senator and Colombian presidential candidate Ingrid Betancourt, holding her for more than six years in which they tortured her and forced her to record proof of life videos shared around the world. Al-Qaeda and the Islamic State killed hostages Daniel Pearl and James Foley on camera.

We don’t yet know what the alleged plotters intended recently in Michigan. But the government charges allege that the men agreed when one said, “Fear will be manifested through bullets.”

Danielle Gilbert (@_danigilbert) is an assistant professor of military and strategic studies at the U.S. Air Force Academy. The ideas expressed in this article are the author’s and do not represent the U.S. Air Force Academy, Department of the Air Force, or Department of Defense.