Having spent 25 years chasing spies and anyone cooperating with our sworn foreign enemies, I’ve learned a thing or two about individuals like Papadopoulos. These are the ones that get caught early in an investigation because they did something blatantly illegal. Papadopoulos made the mistake of lying to FBI agents, making him low-hanging fruit for cooperation. It might have been simple as telling him, “There is a bus leaving town and there is one seat on it. Everyone else is going to get hammered who doesn’t jump on board.”

Those inexperienced with the full weight of a federal prosecution usually buckle quickly and I suspect this is what happened with Papadopoulos. Becoming a cooperating witness is not an easy decision, but it is always better than being the focus of a federal investigation. Just knowing that the FBI at some future moment could knock on your door is often incentive enough.

Sometimes a conspirator is hesitant to cooperate because they don’t want to be perceived as an informant or they are trying to protect their future. This is where the FBI agents tell the hesitant witness that they can be a hero, rather than a snake enjoying the hospitality of our federal prison system.

If this doesn’t work, agents might need to call in a prosecuting attorney to scare the witness even further. In one espionage case I worked, we desperately needed one of the suspects to turn and help us prosecute others. But the suspect was reluctant to be, in his words, “a snitch”—even though by this time his own attorney was counseling him to cooperate. The government was willing to cut a deal and reduce his prison sentence on the condition that he testified truthfully. Still we got resistance.

Finally, we had the federal prosecutor meet with the reluctant individual and his attorney. It was not pretty. The attorney said, essentially, “This is espionage. This is assisting our sworn enemy. The jurors will hate you no matter what, but I promise you and your attorney that I will throw the prosecutorial book at you if you don’t cooperate. I will not accept any deal from your attorney after today, and when the time comes for your trial, I will beat you like a seal pup on a sheet of ice and watch you bleed.” Twelve seconds later, we had cooperating suspect.

I suspect Mueller will be much smoother than this, since he wields a lot of power. But regardless of his style, he has already communicated that he intends to conduct his investigation aggressively. The lives of all involved in the Russia matter changed drastically on Monday. Some will get suspicious as to who they talk to; some will lose sleep over emails or phone calls they have made. Spouses will warn them not to be the last person to not cooperate. So will blustering attorneys, who will exclaim publicly their clients are innocent while offering them to the authorities as federal witnesses in exchange for time.

Even made Mafia members now routinely cooperate in criminal cases; everyone looks out for themselves. Washington is no different. Any remaining conspirators in the Russia collusion investigation will end up cooperating under pressure. If they’re resistant, investigators can promise them a Rule 35 appearance, which is when investigators testify on behalf of a convict—due to their cooperation—to help them get released early. Just that promise, alone, might be all a witness needs to provide evidence that could bring down a president.

Joe Navarro is a former FBI special agent and counterintelligence supervisor. He is the author of Three Minutes to Doomsday: An Agent, a Traitor, and the Worst Espionage Breach in U.S. History.