The Byte's His Beat

updated 11/21/1994 AT 01:00 AM EST

originally published 11/21/1994 AT 01:00 AM EST

MARTIN WAS JUST AN ORDINARY 13-year-old—lonely and confused, desperate to vent his adolescent angst. And so, befitting a child of the information age, he logged onto a computer "chat" board where he could talk electronically with other computer buffs in his hometown of San Jose, Calif.

Almost immediately, a message flashed across his screen: "Do you like girls or boys?" queried someone using the handle "Thieves."

"I guess I feel uncomfortable around girls," Martin replied. "Boys are okay."

For 2½ months he and Thieves, who soon revealed his name was Don, shared stories and secrets in cyberspace. Finally, Martin's computer confidant took the plunge. "Let's meet," Don suggested. "Okay," Martin replied. "I'll be on my bicycle."

The next day 51-year-old insurance broker Donnell Howard Hughes pulled his white Ford Pinto into the parking lot of Harry's Hofbrau, a suburban restaurant. He stepped out of the car, leaving behind his wedding ring, a bag filled with condoms, a vibrator, a tube of K-Y Jelly and a deck of cards for playing strip poker. There, at last, he met "Martin"—Sgt. Jim McMahon, head of the San Jose Police Department's Hi-Tech Detail, who arrested Hughes for soliciting a minor for sexual activity. (Hughes pleaded guilty in February and was sentenced to five years probation.) "Imagine his surprise," McMahon says, "when he discovered that I had as much gray hair as he did."

The "alienated teenager" is a stock role for McMahon, who is one of the nation's foremost cybercops—a small (estimated at a few thousand) but growing group of federal, state and local police—as well as private citizens—who fight crime along the information superhighway. Aside from on-line pedophiles and pornographers, McMahon and his breed track down digital desperadoes who invade security systems, skim dollars out of people's credit-card and bank accounts and steal software, microchips and other electronic accoutrements. As the world becomes computer literate, such misdeeds are the wave of the future. Notes J. Buck BloomBecker, director of the National Center for Computer Crime Data in Santa Cruz, Calif.: "User-friendly translates to abuser-friendly."

A former street cop long fascinated by computers, McMahon took over the Hi-Tech Detail in 1990, built it into a four-man unit and raised it to national prominence. "Jim is the prototype of the police officer of the 21st century," says William Tafoya, a special agent for the FBI who specializes in electronic crime. McMahon's self-appraisal is at once unsparing and immodest: "I'm egotistical, arrogant and smart."

Crammed into a third-story corner of police headquarters in San Jose's Civic Center, McMahon's office space adjoins a room strewn with stolen computer terminals and laptops. Some of the goods were seized from the homes of obsessed hackers, a forbidding undertaking. "You can tell a hacker's house," says McMahon, "because you work your search like a geological survey through the moldy, crusted pizzas."

He must also cope with more traditional hazards, which is why McMahon, who stands an imposing 6'2" and can usually be found garbed in a sport shirt and gritty tennis shoes, always keeps a 9-mm Smith & Wesson strapped to his right hip. For instance, a raid on the house of some computer thieves revealed an arsenal including an AR-15, seven handguns with their registration numbers filed off and a sawed-off shotgun. "Whether it's dope or it's chips," says SJPD cop Bruce Toney, an investigator with McMahon's outfit, "people want to protect their investment. This isn't white-collar crime."

Most often, though, it's guile and not gunplay that carries the day for McMahon. Black-market chips and hard drives (two of the priciest items) can change hands a dozen times within 72 hours, until they disappear inside computers and become virtually untraceable. In one case, Mc-Mahon played the part of the owner of a small computer store who was willing to fence stolen chips, while the rest of his crew posed as employees. The sting ended with an arrest and the discovery of a carton filled with $100,000 worth of chips in the trunk of the perpetrator's car.

The Texas-born McMahon lives outside San Jose in a rambling, two-story house with his wife of 16 years, Mara, their 10-year-old daughter and 5-year-old son (whose names he won't divulge for security reasons), a rambunctious border collie and a 13-year-old cat. He grew up nearby, part of the nation's first generation of computer techies. Educated at the University of California at Davis, McMahon joined the San Jose police in 1976, sometimes working undercover on the vice squad, where he formed the Child Exploitation Detail and often posed as a pedophile. "You divorce yourself from it," he says. "Just as you divorce yourself from the bodies on the road after an accident."

It is a dark world McMahon—who is on call 24 hours a day—enters late at night, when he transforms himself into a hacker in the privacy of his basement computer room. Far removed from the end of his official workday, long after his family has gone to sleep, the online chameleon continues to roam the back alleys of cyberspace, insinuating himself onto the myriad "pirate" boards where criminals lurk.

"So many crooks," sighs McMahon as he logs onto his computer. "And so little time.".

RICHARD JEROME
STANLEY YOUNG in San Jose

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