"I've been reading 'Serpentine,'" said my sister-in-law in oh-wow tones. "I hope you don't ever run into anyone like that."

I have no trouble seconding that notion. My sister-in-law's current book choice tells the story of Charles Sobhraj, a con man and killer. He was caught -- finally -- in 1978, after leaving a bloody trail from Hong Kong to Turkey. His victims were trusting tourists he contrived to pick up or casually "befriend."

It's a gory story all right, and it can't help but make you wonder about a lot of things:

Was Sobhraj unique, or should you take in what you see nightly on the tube and deduce that travelers just might be hip-high in his brethren? How many tourists are victimized anyway? Are they gulled in vast numbers or do they get their pockets picked more often in travelers' check commercials than they do in real life?

After consulting with various keepers of the news on crime and fraud, I felt as though I were in the grand old days of the Saturday afternoon double-feature horror show.

I listened attentively to stories about robberies of sleeping car passengers on European trains, to American Express' claim of paying off on $50 million in forged travelers' checks in three years, to reports of rapes involving visitors to Hawaii.

I heard of gold earrings torn from the pierced ears of an American woman in Bogota, of bus station patrons in Los Angeles having their pockets picked when they dozed off, of an ailing man traveling through Seattle whose cash, airline ticket and credit cards were openly plucked from his person by a woman soliciting in the airport terminal for a religious group.

A U.S. foreign service officer told me of a summertime stunt pulled in Rome: Purse-snatchers, he explained, would zero in on a girl wearing a tube top, yank it down, and of course be rewarded with what they wanted when she instinctively used both hands to cover herself.

Bad? Well, for sure it's not good. Yet if you reach for details on crime and tourism, you'll find it's nearly impossible to say if there are too few people sounding alarms or too many:

Although American Express has claimed that theft is the most common cause of travelers' check losses, in fact, the company's study sample shows a greater percentage attributable to simple loss. (Sneak theft from hotel rooms accounted for 12 percent, theft from automobiles 8 percent, unarmed street theft by pickpockets and purse-snatchers 5 percent, theft from homes 21 percent, and armed robbery 1 percent. Altogether a total of 47 percent was attributed to theft as contrasted to 53 percent involving some form of accidental loss.)

At the same time, all conclusions were based on a look at 5,050 refund claims (out of a 190,000 total), selected because they represented losses "above a certain dollar value." No other totals or purchase figures were revealed. It's thus anybody's guess what the full story is, regardless of the distressed faces in the television commercials and cries for "Mr. Wong! Mr. Wong!"

The Travelers Aid Society keeps no statistics on victimized travelers who turn up on its doorstep but, to cite one example, the San Diego director says his office sees perhaps one such person a week "or less."

Police can give totals of muggings, purse-snatchings and the like, but they don't divide victims into residents or nonresidents. Bunco fraud figures don't differentiate either. It's therefore impossible for them to say if travelers are picked on any more or less than anyone else.

The State Department annually fields reports on some 10,000 missing persons. The figures, though, are grimmer than the facts. About 5,000 "just haven't checked in with mother," says a spokesman, and the other half are not really missing either, merely wanted in a hurry. In the end, the figure is reduced to 10 or 20 "seriously missing" persons each year.

Rape data is inadequate nationwide, to put it mildly, and Hawaii's ability to make statistical breakdowns as they relate to women tourists is possibly unique. By the same token, it should be noted that Honolulu's police-reported rape totals are still proportionately less than those of, say Las Vegas and Los Angeles. Perhaps the most important thing about this "trouble in paradise" report is its value as a reminder: It's a mistake for a woman to throw away normal cautions just because she's "on vacation" and supposedly in idyllic surroundings.

If the big picture is murky, the fact remains that as a group, travelers do make terrific targets. Away from home, we frequently carry more valuables than we normally would, and we become psychologically more vulnerable for being off our own turf. Furthermore, if we are hit on vacation, chances are we won't be around to testify if the culprit gets caught.

When we're paying big bucks to "have a good time," we also tend to let our attention slip -- and forget that the evil lurking in other men's minds has lost its status as a joke phrase. Charles Sobhraj for sure directed move savage notions at tourists than almost anyone in history. But, then again, you could take that as encouraging. More practical, though, is to take it as a hint and learn more of what to look for and what to look out for.