The victim, Michael Steinberg, 64, was hospitalized in stable condition. Speaking by telephone to reporters who gathered outside the hospital, he said the attack was unprovoked.

The assailant "never spoke," Steinberg said. "I think he was out of his mind."

The attacker snatched the two saws from a cart being used by workers upgrading the public address system at a subway station a few blocks south of Columbia University. He assaulted Steinberg moments after taking a swipe at another rider and missing, police said.

"He looked at me and before I knew it he was attacking me," Steinberg said of the pre-dawn attack. "The motor kept going on. He was trying to cut through me."

Steinberg said the attacker finally paused to demand money, then bolted out of the station with his wallet and the power tools. The saws were later found in a trash can.

Williams was in police custody Thursday evening. There was no telephone listing for him at the home address provided by police.

The attack came two weeks after a Boston man was charged with stabbing four people - three of them tourists - over a 13-hour period in the subway and the theater district in Manhattan.

Uhilamoelangi said the couple had arrived in the area earlier this week to discuss political reforms with members of the region's Tongan community. Uhilamoelangi, a Tonga native and East Palo Alto resident, helped arrange the visit.

San Mateo County Coroner Robert Foucrault confirmed that two members of Tonga's royal family died in the crash. But he would not release their names until the Tongan government made an official announcement.

The driver of the red Ford Explorer carrying the two also was killed, the California Highway Patrol said.

Edith Delgado, 18, of Redwood City, allegedly was racing her car at speeds up to 100 mph on a highway in Menlo Park, about 30 miles south of San Francisco, when she tried to pass the SUV in which the royal couple was traveling, said highway patrol Officer Ricky Franklin.

Delgado's car slammed into the driver's side of the Explorer, causing it to swerve across several lanes before tumbling to a stop on its roof, Franklin said.

Delgado, who was not injured, was jailed on suspicion of vehicular manslaughter and engaging in a speed contest, Franklin said.

Tonga - a 170-island archipelago about halfway between Australia and Tahiti - has a population of about 108,000 and an economy dependent on pumpkin and vanilla exports, fishing, foreign aid and remittances from Tongans abroad.

Now the last monarchy in the Pacific, Tonga has been a Polynesian kingdom and a protectorate of Britain, from which it acquired independence in 1970. It is ruled by 88-year-old King Taufa'ahau Tupou IV.

New Zealand Foreign Minister Winston Peters praised Prince Tu'ipelehake's efforts at reforming Tonga's political system and said it was a "tragedy" that he died while traveling to the United States to seek out opinions of Tongans.

"He pursued this goal with sensitivity and perception, mixed with a strong determination to achieve progress," Peters said in a statement. "This earned wide respect in New Zealand as well as in Tonga, where he was often called the Prince of the People."

A large crowd had gathered, some trying to put out the blaze, others just watching.

Some 37 villagers were killed on the spot and six died in hospital, Xinhua said.

"The villager's home was blasted into rubble," it said, quoting a local official.

Deadly blasts caused by privately stored explosives are not rare in Shanxi, where about a quarter of China's coal is produced.

In April, at least 33 people were killed and buildings flattened in the city of Yuanping when explosives stored by a former coal-mine owner blew up.

Ten villagers were killed in a gold-mining town in Shanxi in a blast at a family dynamite workshop in June.

It is behavior that's more commonly seen in neutron stars that have been around for several million years, researchers say.

"The behavior we see is especially puzzling in view of its young age, less than 2,000 years," said study leader Andrea De Luca of the Istituto Nazionale di Astrofisica (INAF) in Milan. "For years we have had a sense that the object is different, but we never knew how different until now," De Luca said.

The finding is detailed in the July 7 issue of the journal Science.

Novel stage?

Called 1E161348-5055, or 1E for short, the object is embedded almost in the exact center of RCW103, a supernova remnant located 10,000 light-years away in the constellation Norma. Astronomers think that 1E and RCW103 were both born in the same catastrophic event.

Like other neutron stars, which form when a star at least eight times more massive than the Sun runs out of fuel and explodes as a supernova, 1E is estimated to be only about 12.5 miles (20 km) across.

One explanation for the neutron star's strange behavior is that it might be a magnetar, an exotic subclass of highly magnetized neutron stars. Of the dozen or so magnetars that are known, however, most usually spin several times per minute-much faster than 1E.

This explanation might still work, however, if the magnetar is surrounded by a debris disk that is helping to slow down the neutron star's spin. This scenario has never been observed before and would mark the discovery of a novel stage in neutron star evolution if confirmed.

One or two?

Another explanation, scientists say, is that 1E is part of a binary system with a normal, low-mass star with only half the mass, or less, of our Sun.

Such X-ray binary systems are known, but they usually involve systems that are millions of times older than 1E.

Despite the many speculations, the short answer is that scientists simply don't yet know how to explain 1E's strange behavior.

"RCW103 is an enigma," said study team member Giovanni Bignami, director of the Centre d'Etude Spatiale des Rayonnements (CESR) in France. "When we do figure this out, we're going to learn a lot more about supernovae, neutron stars and their evolution."