PARIS, France (CNN) — The suspected ringleader in last week’s bloody terrorist attacks in Paris was killed in a pre-dawn raid Wednesday on an apartment building north of the French capital, the Paris prosecutor’s office confirmed Thursday.

Authorities zeroed in on a building in the northern Paris suburb of Saint-Denis after picking up phone conversations indicating that a relative of Abdelhamid Abaaoud, who authorities believe coordinated the shootings and bombings that killed 129 people, may have been there, a Belgian counterterrorism official said. French police believed Abaaoud himself was then still in the country, though they didn’t know exactly where.

It turns out Abaaoud was in that building in Saint-Denis. And after a violent firefight that included explosions and gunfire, he was dead.

In a statement released Thursday, the Paris prosecutor’s office said that Abaaoud’s body was found in the Saint-Denis building riddled with bullets. The office said that he has since been positively identified.

Police fired around 5,000 rounds of ammunition in the Wednesday morning confrontation, an operation that suggested authorities were making headway in their investigations into Friday’s terrorist rampage across Paris but also fed fears of more violence in a city already on edge.

By the time the dust settled and the standoff came to an end, two suspects and a police dog were dead, eight people were in custody, and five police officers were slightly wounded.

Some residents in the area told CNN they had seen Abaaoud recently in the neighborhood and at a local mosque.

Paris Prosecutor Francois Molins only said Wednesday that Abaaoud was not among the eight people detained. Neither was Salah Abdeslam, a French citizen suspected of involvement in Friday’s coordinated wave of terrorist violence carried out in the name of ISIS.

Murky movements

Speculation about Abaaoud’s activities and movements has proliferated since officials began linking him to the Paris attacks in recent days, with many observers assuming he was operating in Syria.

The rumors became even more frenzied early Wednesday as it emerged that he was the potential target of the raid in Saint-Denis, the same area where ISIS suicide bombers had blown themselves up Friday outside the national stadium as the French soccer team played Germany inside.

Abaaoud has bragged in the past of being able to move between Syria and Europe at will. Western intelligence agencies are reported to have tried to target him in the months prior to the Paris attacks without success.

As the police operation neared its end Wednesday, wildly varying reports suggested he could be dead, alive or not even in France.

French officials remained cagey, however, saying the identification of the second body hadn’t been completed.

Suspects appeared ‘prepared to act’

The identities of most of the eight people detained by police are also unclear. They include the person who loaned the apartment to the suspected terrorists and his friend, according to authorities. Two of the eight were hospitalized, the Interior Ministry said.

Whoever those inside the apartment were, they may have been preparing to unleash more terror on the streets of Paris.

The suspects appeared to be “prepared to act” in another possible attack, Paris Prosecutor Francois Molins said, noting their weaponry, structured organization and determination.

Investigators are also still digging into other angles related to Friday’s attacks, including the whereabouts of Abdeslam, the French suspect who was last seen heading toward the Belgian border in the hours after the massacres took place.

Officials are working to piece together where the terrorists were in the days and hours leading up to the attacks, and with whom they had contact. Seven of the attackers were killed during the attacks, mostly by blowing up the explosives strapped to their bodies.

Attacker’s cell phone found in trash bin

Investigators have encountered at least one piece of evidence that could help them in their search: One of the attacker’s cell phones was found in a trash bin outside the Bataclan concert hall, where most of Friday’s victims were gunned down.

A message on the phone, according to Molins, said, “Here we go, it’s starting.”

Authorities are trying to determine whom the message was sent to, he said.

The Saint-Denis police operation is the most dramatic among wave upon wave of raids across France in the aftermath of the Paris attacks.

Authorities are using the state of emergency declared by President Francois Hollande to carry out a widespread clampdown on potential terrorist threats, detaining dozens of people, putting more than 100 others under house arrest and seizing an alarming array of weapons.

Hollande, who wants to extend the state of emergency for three months, held up Wednesday’s deadly clash between police and suspects in Saint-Denis as further proof that France is “at war” with ISIS, which is notorious for brutally imposing its warped interpretation of Islam on the millions of people living in the territory it controls in Syria and Iraq.

France wants wider coalition against ISIS

The Paris attacks and ISIS’ claim of bringing down a Russian passenger jet over Egypt last month have underscored the extremist group’s desire to expand the reach of its terror.

Already part of the U.S-led coalition that’s bombing ISIS targets in Syria and Iraq, France has stepped up its airstrikes on the militants since the Paris attacks.

Hollande said he would appeal to world leaders to form a wider coalition to go after ISIS, including meeting next week with U.S. President Barack Obama and Russian President Vladimir Putin.

Russia has taken military action in Syria independently of the U.S.-led coalition, attacking ISIS but also other groups opposed to Syrian President Bashar al-Assad, a close ally of Moscow.