TOULOUSE, France (AP) -- Police spread out across southern France by the hundreds Tuesday, hunting for an expert gunman suspected in three deadly attacks who may have neo-Nazi ties or grudges against minorities.
The manhunt took place as friends and family tearfully mourned four people slain at close range Monday at a Jewish school in the city of Toulouse -- a rabbi, his two young sons and a young girl.
Authorities suspect the school killer was also behind two recent attacks in the same area on French paratroopers that left three soldiers dead and one seriously wounded. The victims were of North African and French Caribbean backgrounds.
A "monster" is on the loose in France, French President Nicolas Sarkozy declared, vowing to track him down.
"There are beings who have no respect for life. When you grab a little girl to put a bullet in her head, without leaving her any chance, you are a monster. An anti-Semitic monster, but first of all a monster," he said.
Focus fell Tuesday on three paratroopers who had been expelled from their regiment near Toulouse in 2008 for neo-Nazi sympathies, a police official said. The killer on Monday handled large-caliber guns with expertise, leading some to suspect he had a military or police background.
France was reeling Tuesday after Monday's shooting, the deadliest school shooting in the country and the bloodiest attack on Jewish targets in decades. Schools across the country held a moment of silence Tuesday to honor the victims, who were heading to Israel for burial.
Interior Minister Claude Gueant described the suspect as "someone very cold, very determined, very much a master of his movements, and by consequence, very cruel."
Gueant said the attacker was wearing a camera around his neck that could be used to film and post video online. He said that gave investigators new clues to the killer's "profile," although he admitted they don't appear to close to an arrest.
He mentioned the three paratroopers who had been kicked out but insisted it was just one of many leads being investigated and "not favored any more than the others."
Norway's Anders Behring Breivik, the right-wing extremist who killed 77 people in a rampage last year, had suggested in an online manifesto before the killings that a camera could be used to film such ethnic-cleansing "operations." There was no mention in his indictment that he used one.
In Monday's shooting, the attacker first gunned down a rabbi and his two young sons, then chased down the daughter of the school principal, shooting her dead at point-blank range. Reports of the children's ages varied, with the Israeli Embassy saying Tuesday the boys were 3 and 5 and the girl was 8.
Police are investigating the possibility that the killer is a former soldier with psychological troubles and racist and anti-Semitic views. One soldier was briefly held then released over the weekend, after the paratrooper killings but before the school shooting, the police official said. The official was not authorized to speak while the investigation is ongoing.
At the site of the second paratrooper killing, police found the charger for the gun used in all three attacks, but found no fingerprints or DNA on it, the official said.
Police are studying the online communications by the first paratrooper killed. He was shot March 11 after posting an announcement online to sell his motorcycle, the police official said, and investigators believe the gunman responded to the ad and lured the paratrooper into an isolated place March 10 to kill him.
Behavioral analysts are helping with the investigation, the police official said, and comparing the actions of the suspected perpetrator to those of serial killers and to those such as Norway's Breivik.
Wails and weeping filled the air Tuesday as the school honored the victims, including the rabbi who taught there. Several young men pressed their heads against the rear window a hearse in grief as it drove away.
The rabbi's widow covered her face and held her remaining child, a 1-year-old daughter, dressed in a bright pink dress. The widow's uncle, Marc Alloul, described how the girl woke up in the middle of the night after the killings, calling out, "Papa! Papa!"
Sarkozy, who has played up nationalist themes in his bid for a second term in upcoming elections, sought to stress the overall horror of the crime.
"The children are exactly like you," Sarkozy told junior high school students in Paris after joining them for the moment of silence. "That could have happened here."
He spoke at a public school across the street from a memorial to the French people who helped Jews during the Holocaust, when most of France was occupied by the Nazis.
Sarkozy also talked about the paratroopers killed in two attacks in Toulouse and nearby Montauban. The killer in those attacks also came and went on a motorbike and shot from the same weapon as the one used in Monday's school killing.
"Is it because they had come back from Afghanistan? Is it because they came from visible minorities? We don't know," Sarkozy asked about the paratroopers who were killed.
The French Defense Ministry has said the paratroopers didn't serve in Afghanistan, but one family says their son did. Other families have refused to comment on the topic.
France is holding a two-pronged presidential election on April 22, with a runoff expected May 6, in which issues about religious minorities and race have gained prominence. Sarkozy, a conservative, is known for his hard line against increased immigration.
Sarkozy also met Tuesday with members of France's Jewish and Muslim community. France has western Europe's largest population of both Jews -- about half a million -- and Muslims -- about 5 million.
The terror threat level was raised to scarlet across a swath of southern France -- the highest level since the four-point system was created in 2003.
In Toulouse, France's bustling fourth city, streets were emptier than normal. In one main square, Place Wilson, a dozen police officers were on patrol, some guarding the subway entrance.
In Paris, police bearing automatic weapons stood in front of Jewish schools.
"It's impossible not to imagine the worst, because it can happen to any child in France," said Mendy Sarfati, a father dropping his three children off at a Jewish school in Paris. "We want to put this drama behind us and for the French Republic to draw lessons from it."
Sylvie Corbet and Jeffrey Schaeffer in Paris and Karl Ritter in Stockholm contributed to this report.