A young German, who recently lost his job, shot and killed two former bosses yesterday then took a taxi to his old high school and killed the principal and himself as hundreds of students ran for cover.

The man, believed to be 22, wore army camouflage and carried two pistols and two pipe bombs as he apparently settled old scores. None of the more than 400 students was injured.

"I don't understand this world anymore," said Hubert Bartls, whose 16-year-old daughter was among those trapped in the school.

The chief state law enforcement official, Guenter Beckstein, said the shooting spree clearly involved personal grudges, not random violence.

Bavarian governor Edmund Stoiber, who is running for chancellor in this year's national election, expressed sorrow and shock at the "incomprehensible events."

Police said the violence began about 8 a.m. when the man, whose identity was not made public, walked into the packaging company in Eching and shot his former boss, 38, and a foreman, 40. Both men died at the scene.

The assailant, who had kept his taxi waiting through the shootings, then took the cab 12 miles back to Freising where he began the assault on his former high school, which specializes in vocational training.

The man walked into the school shooting, then set off a pipe bomb. Witnesses said he entered the school office and asked for his former word processing teacher. When told the teacher was not at school, the man fatally shot the principal and wounded another teacher in the cheek, police said.

Students may grade each other's work in class without violating federal privacy law, the Supreme Court ruled yesterday in the case of a learning disabled boy whose classmates ridiculed his poor scores and called him a "dummy."

The 9-0 ruling upheld the common schoolroom practice of having students swap homework, quizzes or other schoolwork and then correct one another's work as the teacher goes over it aloud. Sometimes the teacher then has students call out the results, and the teacher records them.

"Correcting a classmate's work can be as much a part of the assignment as taking the test itself," Justice Anthony M. Kennedy wrote for himself and seven colleagues. Justice Antonin Scalia filed a separate concurring opinion.

"It is a way to teach material again in a new context, and it helps show students how to assist and respect fellow pupils," wrote Kennedy, a former law professor who still teaches several classes a year.

An Oklahoma mother challenged the practice as embarrassing and a violation of a federal law protecting the privacy of student education records, such as a transcript.

Kristja Falvo's case became a battle between the education establishment and conservative groups interested in promoting parental rights in schools.

Students and teachers should not have the power to reveal another student's record - in this case a grade or teacher's note - without a parent's permission, Falvo and her supporters argued.

Her children's school, joined by other school districts and the Bush administration, argued that the 1974 privacy law was not meant to be interpreted that way. In passing the law, Congress was concerned about preserving the privacy of the final, institutional records of a school, not the results of one day's class work, the Bush administration argued.

Illegal immigrants crossing the Arizona-Mexico border could be facing heightened danger as drug smuggling organizations move to the small mission community of Altar, about 60 miles south of the Arizona border, law enforcement officials said.

Turf battles have always been a part of the drug traffickers' game, said Rene Andreu, resident agent in charge of the U.S. Customs Service's investigations office in Sells. Tossing illegal immigrants into the mix can only complicate a dangerous situation, he said.

"There's always a possibility that some migrant workers will cross paths with these people, and that may not necessarily be good for them," Andreu said. "We'll address it. We're reacting to it now."

Officials on both sides of the border say sophisticated, armed drug trafficking organizations with roots in Ciudad Juarez, Chihuahua, to the east and Tijuana, Baja California Norte, to the west have been moving to Altar.

From there, illegal cargoes are driven to the border at Sasabe and even more remote and isolated crossings to the west.

Throughout last year and as recently as last month, the U.S. Border Patrol shifted more agents and resources to the western desert in anticipation of an increased flow of migrants through the region. The move led to more drug seizures, primarily of marijuana.

The outcome was more violent and determined efforts by drug smugglers moving into the region.