People place flowers and candles on Sunday in the Place de la Bourse to pay tribute to the victims of the attacks in Brussels. (Sylvain Lefevre/Getty Images)

For years, Brussels has been the epicenter for European outrage over the CIA’s terrorist interrogation program. Now it is Belgium that has some explaining to do for its failure to effectively interrogate a high-value terrorist — an interrogation that may have foiled last week’s deadly terrorist attacks. The carnage is a direct result of Europe’s refusal to accept that terrorists must be treated differently than common criminals.

When Salah Abdeslam, believed to be the logistics chief for an Islamic State terrorist cell, was captured, Belgian officials followed law enforcement procedures with precision. They provided Abdeslam a lawyer, told him he had the right to remain silent and put him into the Belgian criminal-justice system. Four days later, the terrorist cell carried out bombings in Brussels that killed 35 people — including at least four Americans — and injured hundreds more.

Astonishingly, officials did not question Abdeslam at all for his first 24 hours in custody. He spent Friday night in the hospital recovering from a leg wound sustained in the raid. When he was finally returned to the police on Saturday, he was questioned by authorities for a grand total of . . . two hours — and then was not questioned again until after the attacks. Why? “He seemed very tired and he had been operated on the day before,” a senior Belgian security official told Politico.

He seemed tired? That’s precisely when they should be interrogating him. The CIA used sleep deprivation as one of its most effective interrogation tools. But for Belgians, a terrorist’s exhaustion is a reason to stop questioning, not intensify it.

But here is the most incredible part: During those two hours of questioning, The Post reports, “investigators did not ask . . . about his knowledge of future plots.” Seriously? Abdeslam was the logistics chief for the Brussels-based terrorist cell that carried out both the Paris and Brussels bombings. According to the New York Times, “He was the fixer, renting cars, finding apartments, picking people up and dropping them off.” He could have identified the other members of his cell; the safe houses they used; how they communicated, moved money, picked travel routes; and — most important — the targets they had selected.

Belgium was left reeling after three attacks left at least 31 people dead and more than 200 injured March 22. The terror began unfolding during peak rush hour, and ended with at least one suspect still at large. (Deirdra O'Regan/The Washington Post)

But investigators did not bother to ask him about plans for new attacks. Instead, The Post reports, they “concentrated solely on the Paris attacks . . . and then no other discussions were held until after Tuesday’s attacks.”

The mind simply boggles.

Investigators had found unused detonators and weapons in a safe house with his fingerprints. Did it occur to them to ask what he had intended to use them for? Apparently not.

Abdeslam’s questioning is a textbook example of why the law enforcement model for interrogating terrorists is a disaster. As we saw in Brussels, law enforcement officials are in no hurry to extract answers from a detainee, because they are questioning terrorists after an attack has occurred. Their goal is to extract a confession in order to secure a conviction. In such circumstances, patience is a virtue.

But in an intelligence-driven interrogation, patience is deadly. Interrogators are trying to get information from the terrorist quickly, before an attack occurs. In such circumstances, you need to take a terrorist from a state of defiance to a state of cooperation quickly. Speed is of the essence.

It is simply unconscionable that Abdeslam was allowed to protect the identities of cell members and their plans for the Brussels attacks. But that is only the beginning of the shameful incompetence on display here. Not only did officials not ask Abdeslam about future attacks, but also they compounded that error by holding multiple news conferences in which they bragged about his arrest and boasted how well he was cooperating. This was a fatal mistake.

Belgian officials should never have publicly acknowledged Abdeslam’s capture. When terrorists learn that one of their comrades is being interrogated, they rapidly begin purging email accounts, shutting down phone numbers, dispersing operatives and closing other vital trails of intelligence — and in this case, likely accelerating attack plans. But if a terrorist’s capture is kept secret, these intelligence trails may remain warm for some time — allowing officials to exploit them as they extract information from the detainee.

This case demonstrates the need for some form of secret detention and an intelligence-driven approach to interrogating captured high-value terrorists. It does not mean, as Donald Trump has suggested, that Abdeslam should have undergone waterboarding and “a lot more.” In the CIA’s experience, two-thirds of detainees cooperated without any enhanced interrogation techniques at all. Just the experience of disappearing into secret detention — with no idea where they were and no lawyer present — was enough to get them talking.

Officials in Europe and the United States need to wake up and change their approaches. The Islamic State released a video over the weekend featuring two terrorists, allegedly Belgian nationals, celebrating the Brussels attacks from inside Iraq. One of them looks into the camera and declares, “This is just the beginning of your nightmare.”

If we keep treating terrorists like common criminals, that nightmare will soon become reality.

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