Police are hunting for vandals who chopped fiber-optic cables and killed landlines, cell phones and Internet service for tens of thousands of people in Santa Clara, Santa Cruz and San Benito counties on Thursday.

The sabotage essentially froze operations in parts of the three counties at hospitals, stores, banks and police and fire departments that rely on 911 calls, computerized medical records, ATMs and credit and debit cards.

The full extent of the havoc might not be known for days, emergency officials said as they finished repairing the damage late Thursday.

Whatever the final toll, one thing is certain: Whoever did this is in a world of trouble if he, she or they get caught.

"I pity the individuals who have done this," said San Jose Police Chief Rob Davis.

Ten fiber-optic cables carrying were cut at four locations in the predawn darkness. Residential and business customers quickly found that telephone service was perhaps more laced into their everyday needs than they thought. Suddenly they couldn't draw out money, send text messages, check e-mail or Web sites, call anyone for help, or even check on friends or relatives down the road.

Several people had to be driven to hospitals because they were unable to summon ambulances. Many businesses lapsed into idleness for hours, without the ability to contact associates or customers.

More than 50,000 landline customers lost service - some were residential, others were business lines that needed the connections for ATMs, Internet and bank card transactions. One line alone could affect hundreds of users.

"It was substantial," said John Britton, spokesman for AT&T.

Authorities throughout the area said Thursday night that nobody had sought help from fire or police officials. But only the coming hours, and maybe days, will tell if there were emergencies nobody knows about yet. Officials worried that some people might have become incapacitated before they were able to summon help without a phone.

"We don't know what this has done to people's lives," said Liz Kniss, president of the Santa Clara County Board of Supervisors. "I'm incredibly troubled by it.

"We haven't experienced a major catastrophic emergency today. But we don't know."

FBI agents, phone company managers and local police said they were scouring the vandalism sites for evidence and aggressively searching for the perpetrators. Potential penalties include criminal charges of vandalism, heavy restitution payments and possibly even worse consequences if someone winds up being hurt directly by the outage.

'We will find who did it'

There is no indication so far of terrorism being involved, said FBI spokesman Chris Carroll.

"Someone purposely cut these cables," said Britton. "They didn't have concern for anyone. We will find who did it."

The first four fiber-optic cables were cut shortly before 1:30 a.m. in an underground vault along Monterey Highway north of Blossom Hill Road in south San Jose, police Sgt. Ronnie Lopez said. The cables belong to AT&T, and most of the service disruption came from this attack.

Four more underground cables, at least two of which belong to AT&T, were cut about two hours later at two locations near each other along Old County Road near Bing Street in San Carlos, authorities said. Two additional lines were sliced on Hayes Avenue in south San Jose.

In each case, the vandals had to pry up heavy manhole covers with a special tool, climb down a shaft and chop through heavy cables. Britton said the four cables cut in San Jose were about the width of a silver dollar and were encased in tough plastic sheath. One cable contained 360 fibers, and the other three had 48 fibers each.

At least 500 total fiber-optic strands were sliced, and each had to be painstakingly spliced back together, requiring hours of work.

Police in San Jose and San Carlos are sharing information, said Cmdr. Rich Cinfio, a spokesman for San Carlos police. Investigators said they had no suspects.

AT&T announced a $100,000 reward for information leading to the conviction of the perpetrators, and Santa Clara County officials declared a local state of emergency.

Extra police, firefighters on hand

Verizon, which depends on AT&T cables in the South Bay, reported that its 52,214 landline customers who lost service in southern Santa Clara County came back online just before 4:30 p.m. Britton said AT&T restored service to all but a couple hundred customers in South San Jose by 7 p.m., and that the remaining lines should be up and running by this morning.

Extra sheriff's deputies, firefighters and police officers heavily patrolled the streets in the affected areas, authorities said. Additional ambulances were on hand at St. Louise Hospital in Gilroy.

"We're having a more visual presence out there in the field," said Sgt. Don Morrissey, Santa Clara County sheriff's spokesman. "We're out there to be the conduit, if you will. We're trying to bridge that communication gap between emergency services and citizens."

The outage was nearly tragic in at least a couple of instances.

Destiny Evans of Gilroy felt faint Thursday morning at her job as an office manager at Ortho Sports in Gilroy. Her boss, Joseph Abmont, called 911 on a landline and cell phone but couldn't get through.

So he put Evans in his car and drove her to St. Louise Hospital, where she was diagnosed with a kidney infection.

"He was my savior," Evans said as she left the hospital later in the day with her boyfriend.

St. Louise spokeswoman Jasmine Nguyen said the hospital was rescheduling elective surgeries out of concern that if something went wrong, it would have no way to contact doctors.

Among those affected by the outage were customers of Verizon, Verizon Wireless and Sprint wireless, which rely on AT&T to carry their phone traffic back to their networks. Cell phone customers at T-Mobile and AboveNet also were affected.

Verizon spokesman Jon Davies said the outage was first reported to the company at 1:25 a.m. He said customers were affected in the Gilroy and Morgan Hill areas. Verizon is the sole provider of landlines in southern Santa Clara County.

Verizon Wireless customers also were affected in southern Santa Clara County and from Watsonville to Scotts Valley in Santa Cruz County.

Rerouting restores some service

At least one of the severed San Carlos lines belongs to Sprint, which lost service to several thousand landline business customers. Crystal Davis, a crisis communications manager for Sprint, said the company was able to restore service to some of its customers by rerouting traffic.

The vandalism comes as AT&T is in talks with the Communications Workers of America for a contract covering more than 80,000 employees, who have been working under their old deal since it expired at 11:59 p.m. Saturday. Union members voted in late March to authorize a strike but have not scheduled one.

Candice Johnson, spokeswoman for the CWA, said union members were not involved in the incidents.

"I can state that CWA members have nothing to do with this at all," Johnson said. "There is an investigation going on, and we'll fully cooperate. But our members are working. They're on the job."

Britton said AT&T has a good relationship with the CWA and was continuing to negotiate with the union on their contract.