Similarly, the penitentiary in Bruges had no defense against a helicopter. There are anti-helicopter nets that could be placed over prison courtyards, but they are expensive and complicated to install. Still, the helicopter pilot later reported that he had not seen a single prison guard in the courtyard when he landed.

Image There are 44 entrances to the huge Palace of Justice courthouse in Brussels, only a few of which have significant surveillance. Credit... Herwig Vergult/Agence France-Presse — Getty Images

To give credit to the police and prison guards, of the six convicts who clambered over the wall of their penitentiary, four were rounded up almost immediately. Most of the other convicts who escaped in recent weeks have been caught, some in Belgium, others in France or Morocco.

The minister of justice, Stefaan De Clerck, is now in the hot seat. A decade ago, Mr. De Clerck was forced to resign as minister after a notorious rapist and murderer, Marc Dutroux, overpowered guards while being transferred to a courthouse without handcuffs, took one of their guns and escaped. He was caught a few hours later, but the event prompted the passage of laws to increase the effectiveness of the police and prisons.

Since early last year, Mr. De Clerck, 57, has been back in the job, helped there by his leadership of the Christian Democrats, a crucial player in the coalition government. In his office in the shadow of the towering, scaffolded dome of the Palace of Justice, he admitted that more had to be done on security, in jails and courthouses. After the Dutroux scandal, he said, most attention focused “more on the human side, on the victims, sexual delinquents, reform of the police.”

The escapes have riveted the public here. Lesley Deckers, 23, lived with her mother in the town of Hoboken, in Flanders, where she grew up playing soccer and taking part in youth clubs. When Ms. Deckers was 18 she converted to Islam.

Her boyfriend, Mohammed Johri, also 23, was a Moroccan man sentenced to five years in prison last year for robbing a toy store and a supermarket. Ms. Deckers hired a sightseeing helicopter, under the pseudonym Kelly Verstraeten, to enable the convicts in Bruges to escape. One local newspaper, Gazet van Antwerpen, ran a photo of her this week, after she was caught by the police, over the headline, “I Did It For Love.”

“It’s a pity she had to go that far,” said Kim Nolf, 32, a Hoboken city official.

Mr. Johri and a fellow escapee, Ashraf Sekkaki, 26, used Ms. Deckers’s beat-up Peugeot, robbed some banks in Flanders, looting about $144,000, according to the local press, then made their way via Spain to Morocco. But the Belgian police alerted the Moroccans, and people in the men’s villages were alarmed by the sudden presence of large numbers of police officers, and turned the men in.