An extraordinary manhunt continues today in France for the motorbike-riding gunman who killed three small children and a teacher at a Jewish school on Monday in Toulouse. Chilling details have surfaced about the latest killings, the third in a spree that saw three French paratroopers killed in broad daylight in Toulouse and neighboring Montauban last week. But the killer, masked by a helmet and careful not to leave DNA behind, remains unknown. President Nicolas Sarkozy has raised the terror-alert level in southwestern France to “scarlet,” France’s highest level, a first. There is fear the killer could strike again at any time—the words “race against the clock” are a fixture on nonstop French TV coverage. And as the nation mourns, the French presidential campaign is suddenly unrecognizable, as politicians struggle to strike the right tone with only a month to go before a crucial election.

At 11 a.m. Tuesday, schools across the country paused for a minute of silence in tribute to the Toulouse dead, Jonathan Sandler, 30, his young sons Gabriel and Arieh, and Myriam Monsonego, the young daughter of the Ozar Hatorah school principal. All four of Monday’s victims, like the three French paratroopers of North African origin killed in the incidents March 11 and 15, were shot at extremely close range, according to forensic evidence, burns and powder residue, revealed today by French authorities. The killer, of slight build and average height, used a Colt .45 in all of the incidents, and a 9mm so-called mini-Uzi in Monday’s school attack. A fourth paratrooper, shot March 15 in Montauban as he withdrew cash from an ATM with colleagues, had a bullet cut through his spine.

In Toulouse, where the Place du Capitole is usually the city’s touchstone gathering point for ceremonies happy or sad, crowds were not permitted to collect in the square to observe a minute’s silence Tuesday morning due to heightened antiterror measures. More than 200 specialist investigators are tracking the attacker and all French law-enforcement services are involved. At a late-afternoon press conference on Tuesday, Paris public prosecutor François Molins said no arrests have been made, but no theories have been or will be thrown out until the killer is caught. To illustrate how much work there is left to do, Molins explained there remain 7,800 hours of video-surveillance footage from Montauban alone to be examined.

Asked whether he feared, given the killer has so far struck at four-day intervals, a new attack after a similar short interval, Molins replied, “You’re asking the question we’re all asking ourselves. We all noted the periodicity. I can’t tell you anything more, except to say that I’ve made the same observation as you.”

French police are looking for a Yamaha T-Max 530 scooter, a powerful model used in all three incidents. Video-surveillance footage has yet to reveal a license plate number, but authorities strongly suspect the motorbike was stolen March 6 in Toulouse. The version used in the first two attacks, on March 11 and March 15, was dark gray, while the vehicle used on Monday was white, but authorities believe it may be the same vehicle modified.

On Tuesday, Interior Minister Claude Guéant, who has said he will remain in Toulouse as long as necessary, revealed that one witness claims the attacker had strapped to his chest a GoPro-style camera, the wide-angle sort used by extreme-sports enthusiasts who may then upload videos to the Internet. Skydivers, for instance—an intriguing example given the paratrooper killings. “It’s one more element, it seems to me, that confirms the psychological profile of the killer,” Guéant told reporters. “All of the witnesses who observed the different crime scenes remarked that it was someone determined, who showed particular cold-bloodedness, great cruelty. And the fact, probably, of filming his activities to watch them again or to broadcast them is one more element that is absolutely horrifying.” But public prosecutor Molins, while confirming the killer wore some sort of harness visible in surveillance footage, could not confirm the harness held a camera. The French press has noted that the so-called manifesto posted on the Web by Anders Behring Breivik before he killed 77 people in Norway last summer suggested attacks be filmed. (Yet, as far as comparisons go, at least one French criminologist favors the sniper who terrorized Washington in the fall of 2002.)

In the hours after the paratrooper killings were connected to Monday’s school shooting, speculation grew about a trio of soldiers from the same Montauban regiment as two of those killed. The three soldiers in question left the regiment after a photo surfaced in 2008 showing them making Nazi salutes over a Nazi flag. Moulins and Guéant have suggested the disgruntled neo-Nazi soldier trail is being explored, but is not necessarily favored over others.

Meanwhile, France’s presidential campaign, only a month before the country votes in the first round of elections April 22, has been turned on its head. Editorialists on Tuesday morning put politicians on notice, calling all candidates to refrain from exploiting the tragedy for political gain. Officially, some top candidates including Sarkozy have put their campaigns on hold, canceling or rescheduling rallies and media appearances. Twenty thousand people had been expected for Socialist frontrunner François Hollande’s rally in Rennes on Tuesday evening, now postponed. Hollande will attend the soldiers’ funeral on Wednesday, alongside Sarkozy, the centrist candidate François Bayrou, and far-right National Front leader Marine Le Pen.

But a veneer of national unity between rivals has quickly shown cracks. Bayrou, one of the few candidates to keep campaign dates this week, appeared to point an accusing finger at Sarkozy, whose discourse had veered further right in recent weeks. Politicians have a duty “to make sure that tensions, passions, hatreds are not at every instant maintained, encouraged, that they aren’t fired up,” Bayrou told a crowd in Grenoble on Monday night. “French society is not well served by passing one’s time opposing, even artificially, even electorally, people against one another.”

French Foreign Minister Alain Juppé shot back on France 2 TV, “Let’s not add the ignoble to the horrible. Let’s not try to take advantage in one way or the other this tragedy that naturally has nothing to do with the election campaign.”

Sarkozy, meanwhile, was criticized for his short speech to children at a school in Paris, where he observed a minute of silence broadcast live on TV on Tuesday morning. “What happened in Toulouse at a denominational school, with children from Jewish families, could have happened here. There could have been the same assassin. These children are exactly like you,” he said gravely. “The assassin hounded a little girl. You must think about that,” he added.

“I think, Monsieur President, that one doesn’t speak to children that way. The adults’ duty is to protect, not unnerve,” Greens leader Cécile Duflot tut-tutted with a tweet. The popular French lawyer-tweeter Maître Eolas added, “Never forget, the candidate who claims to protect you first needs you to be afraid.” While the Socialist mayor of the 4th arrondissement, where the school is located, tweeted that Sarkozy’s speech was “à la George W. Bush.”

Indeed, Sarkozy, whose stature gives him a legitimacy at a time of national mourning that his rivals can’t match, has his own delicate balance to strike. Arnaud Leparmentier, Le Monde’s Elysée correspondent, points to Spanish Prime Minister José Maria Aznar’s reaction to the 2004 Madrid train bombings that killed 191 people three days before elections as the example of what not to do. Aznar jumped to conclusions, quickly blaming Basque separatist organization ETA for the al Qaeda attack. Many believe the error in crisis cost him the election.