PARIS — French investigators tracked down the alleged ringleader of last week’s bloodshed in Paris after getting a startling tip: The Islamic militant wasn’t in Syria but in Europe, plotting yet another attack. A discarded cellphone found near a bloodied concert hall led them to his cousin, then to a suburban Paris apartment where both died in a hail of bullets and explosions.

As a manhunt intensified Thursday for a fugitive connected to the carnage, details emerged about the intelligence operation that allowed authorities to zero in on Abdelhamid Abaaoud, the Belgian-Moroccan extremist they say orchestrated the attacks in Paris and four plots that were thwarted earlier this year.

Two men carry a body into a hearse after Wednesday’s police raid in which the leader of the Paris attacks and his cousin died. A tip from outside Europe and a discarded cellphone led authorities to the apartment building in Saint-Denis. The Associated Press

The narrative provided by French officials raised questions about how a wanted militant suspected of involvement in multiple plots could slip into Europe undetected.

Investigators quickly identified Abaaoud as the architect of the deadly attacks in Paris, but they believed he had coordinated the assaults against a soccer stadium, cafes and a rock concert from the battlefields of Syria.

That situation changed profoundly Monday, when France received a tip from a non-European country that Abaaoud had slipped into Europe through Greece, said Interior Minister Bernard Cazeneuve.

“It was a big surprise when the intelligence came in,” said a police official, speaking on condition of anonymity because the information is sensitive. “There were many people who didn’t take it seriously, but effectively it was confirmed.”

As it turned out, not only was Abaaoud in Europe, but right under the noses of French investigators, a 15-minute walk from the Stade de France, the stadium where three suicide bombers had blown themselves up during the attacks on Nov. 13 that killed 129 people and wounded hundreds.

“We have strong reason to believe that this cell was about to commit massive terror attacks in France,” Prime Minister Manuel Valls said Thursday, speaking on public broadcaster France 2.

DISCARDED CELLPHONE LED TO TERRORISTS

Paris prosecutor Francois Molins said Abaaoud was traced to the apartment in Saint-Denis through phone taps and surveillance.

Two police officials briefed on the investigation told The Associated Press that a cellphone dumped in a trash can outside the Bataclan concert hall – where 89 people were killed – proved crucial. It contained a text message sent about 20 minutes after the massacre began that read: “We’re off, it’s started.”

The phone had contact information for Abaaoud’s 26-year-old cousin, Hasna Aitboulahcen, one of the police officials said, speaking on condition of anonymity because the information hasn’t been released by investigators.

Both she and Abaaoud were killed as heavily armed SWAT teams raided the apartment in Saint-Denis early Wednesday, prosecutors said.

Her final moments were marked by a brief, angry exchange with police before she is believed to have detonated a suicide vest – an explosion that hurled parts of her spine and other body parts onto a police car on the street below.

An audio recording, confirmed by a police official, captured the exchange. As gunshots rang out, an officer was heard shouting: “Where is your boyfriend?”

“He’s not my boyfriend!” Aitboulahcen responded angrily. Then a loud explosion was heard, which police officials said was the bomb in her vest detonating.

Prosecutors said Thursday that a fingerprint check had confirmed that another mangled body found in the heavily damaged building was that of Abaaoud. Eight people were arrested in connection with the raids, including two who were pulled out of the rubble.

Authorities initially gave Abaaoud’s age as 27, but on Thursday, Paris prosecutors said he was 28.

“Abaaoud played a decisive role in these attacks,” Cazeneuve said. “The investigation will establish precisely how this Belgo-Moroccan was involved.”

ABAAOUD CONNECTED TO FAILED PLOTS

Abaaoud was also believed to be behind four of six attacks thwarted this year, including one on a church in the Parisian suburb of Villejuif that was foiled when the would-be attacker shot himself in the foot. French authorities are investigating if Abaaoud was involved in an attempted attack on a high-speed train, where three young Americans tackled a heavily armed man, Cazeneuve said.

In addition, he was suspected of links to two jihadis returning to Europe from Turkey, and a “wannabe jihadi” who upon his arrest in August told French intelligence that he had been recruited by Abaaoud to carry out a “violent act” in France or another European country, the interior minister said.

Abaaoud is believed to have gotten to know some of the attackers responsible for the Paris massacre in the Moleenbeek neighborhood of Brussels, where he grew up, including Brahim Abdeslam, who blew himself up outside a cafe in one of Paris’ trendiest neighborhoods. Abdeslam’s brother, Salah, is still being sought as a suspected accomplice.

Authorities in Belgium launched six raids Thursday in Molenbeek and other areas of Brussels linked to another of the suicide bombers, Bilal Hadfi, a French citizen who blew himself up outside the soccer stadium. An official in the Belgian federal prosecutor’s office said the raids targeted people in Hadfi’s “entourage.”

How and when Abaaoud entered France before his death remained unclear. He had bragged in the Islamic State group’s English-language magazine that he was able to slip in and out of Europe undetected.

Abaaoud was wanted in Belgium, where he was sentenced in absentia this year to 20 years’ imprisonment for serving as an Islamic State recruiter and kidnapping his younger brother, Younes. Belgian authorities say Abaaoud brought the boy, then 13, to Syria last year to join him in Islamic State-controlled territory.

FRENCH RELIEVED BUT STILL CAUTIOUS

News of Abaaoud’s death appeared to ease some tension in a country deeply shocked by the attacks, though officials said the aftermath is far from over.

“We now know that Abaaoud, the brain behind these attacks – one of the brains, because we must be particularly cautious, and we know what the threats are – was among the dead,” Prime Minister Manuel Valls told the lower house of the French Parliament.

He spoke as lawmakers voted to extend a state of emergency for three months. The measure now goes to the Senate, where it likely will be approved. The state of emergency expands police powers to carry out arrests and searches, and allows authorities to forbid the movement of people and vehicles at specific times and places.

Valls had pressed for the extension, and warned Thursday that an attack using “chemical or biological weapons” could not be ruled out, though he did not mention a specific threat.

France requested a meeting of European interior and justice ministers Friday in Brussels to discuss the fight against terrorism. “Everyone must understand that it is urgent for Europe to recover, get organized and defend itself against the terrorist threat,” Cazeneuve said.

French President Francois Hollande was going to Washington and Moscow next week to push for a stronger international coalition against the Islamic State.

Meanwhile, Italian authorities were searching for five people flagged by the FBI in connection with a U.S. State Department warning Wednesday that St. Peter’s Basilica in Rome, Milan’s cathedral and La Scala opera house, as well as churches, synagogues, restaurants, theaters and hotels had been identified as “potential targets.”

French military spokesman Col. Gilles Jaron said Thursday that French forces have destroyed 35 Islamic State targets in Syria since the attacks on Paris.