Among celebrities, fear is increasingly the companion of fame. The murder last July of My Sister Sam star Rebecca Schaeffer, followed by actress Justine Bateman's confrontation with a pistol-brandishing zealot two months later, capped a series of alarming incidents last year involving obsessive fans. At Universal Studios, a former mental patient allegedly shot and killed two guards after they refused his demand to see Highway to Heaven star Michael Landon. Talk show host David Letterman had his Connecticut home broken into four times by a delusional woman who claimed she was his wife. In another incident, actor Michael J. Fox and his recent bride, Tracy Pollan, received 6,000 letters, many containing death threats, from a 26-year-old woman who was upset about their marriage.

Responding to the threats, Fox followed the lead of many other celebrities. "When this sort of thing crops up," he said, "you go to Gavin de Becker. "An L.A.-based security expert, De Becker, 35, provides safety consultation to 120 entertainment figures. Although he doesn't name his clients, his work for Madonna, Tina Turner, Sheena Easton, Robert Red ford, Olivia Newton-John and others has been publicized by various cases. He spoke with correspondent Doris Bacon.

Why do celebrities like Madonna become targets?

A key factor is the increased fascination with the personal lives of media figures and the resulting illusion that we share a certain intimacy with them. Such singers have audiences of 100 million people. Some believe she's singing directly to them. Some believe their destiny is entwined with hers. Some of them are happy to stay home and write her fan letters. And some of them will just think weird thoughts about her. But some of them may go to great lengths to try to make direct contact with her.

What about lesser-known celebs?

An example is Rebecca Schaeffer. Many young actresses like her feel safe because they are not major stars. Robert John Bardo, the man accused of shooting her to death at her Los Angeles apartment, had written a stream of letters to her over a period of two years. He called her agents to get information about where she worked. He went to the set of her TV show and was interviewed by security personnel. He got her address by hiring a private detective. For obsessed fans, someone like Whitney Houston or Elizabeth Taylor may seem unapproachable. Whereas a Rebecca Schaeffer, who is the "girl next door," is approachable.

How do people who may pose a hazard to your clients come to your attention?

They usually will make some effort to communicate with the celebrity who is the object of their obsession. It's not uncommon for a single fan to write hundreds of letters to one of my clients. And some of these communications contain very bizarre things: semen, urine, body parts, dead animals, locks of hair, blood.

Is there a typical person that a public figure should be wary of?

Studies show that more than 90 percent of the people who might deliberately cause harm to a public figure are mentally ill. The other 10 percent are often angry or upset fans. It is impossible to offer a profile of a typical stalker, but they do exhibit common behavior patterns. They're media addicts. They are narcissistic. Many are loners seeking greatness by destroying greatness. Others believe they have a special relationship to some famous person.

What distinguishes the harmless loners from the potential assassins?

Usually some kind of love obsession is involved. In letters from someone who is potentially dangerous, you are more likely to find expressions of shared destiny than of hatred. Ironically, someone who says "I'm going to kill you on Tuesday" may be less likely to act than someone who says "You and I must be united on Tuesday." Somehow the public figure becomes the object of a grand delusion, and the obsessed fan feels there is some kind of meaningful relationship.

How does that obsession turn to violence?

Consider the case of Michael Perry. A Louisiana man, he was an escapee from a mental institution when he began stalking my client [Olivia Newton-John]. He wrote two letters to her saying he wanted to prove to himself that she was real and not just a "Disneyland mirror image." Somehow he convinced himself that she was responsible for dead bodies rising through the floor of his home. He developed an obsession involving my client's eyes and was convinced they had changed colors as a signal to him. He composed a death list of 10 names, including Supreme Court Justice Sandra Day O'Connor. Our firm—we have 23 people—monitored his whereabouts for a year and twice turned him away from our client's estate. Eventually he killed five people, including his mother and father, and shot out their eyes. Fourteen days later he was apprehended in a hotel room near the Supreme Court in Washington, D.C. There were seven TV sets in the room with him—each tuned to static and with eyes drawn on them with a marker.

Is the criminal justice system adequately prepared to deal with such madness?

Unfortunately there is a giant valley between the criminal and mental health systems, into which all kinds of people slip. Ralph Nau, a man we monitored for nearly 3½ years, traveled thousands of miles to Australia, Scotland and Las Vegas, pursuing my clients [Newton-John, Sheena Easton and Cher]. We prevented him from reaching our clients, but he eventually confessed to murdering his stepbrother with an ax and was acquitted on a technicality.

What recourse is available to those clients?

For the time being, we have no choice but to keep going back to court to keep Nau hospitalized on a 60-to-180-day basis, the maximum length of time which current law allows him to be held. The courts do not consider mental disorders permanent. So a patient like Nau can request a hearing almost any time, saying, "I've responded to treatment and I'm ready to go out now."

Should the laws pertaining to the commitment of mentally ill people be changed?

Only a very small percent of the mentally ill pose a threat to society, and I don't believe they should be locked up for some hypothetical act they might commit. But I do believe that the laws should be strengthened to deal with cases where evidence strongly indicates that someone poses a real danger to someone else. Another case of particular concern now involves Arthur Jackson, a drifter who stalked actress Theresa Saldana to Los Angeles in 1982 and stabbed her 11 times. He was convicted of attempted murder but is now scheduled for release this April. In the meantime he has frequently indicated in letters that he still intends to kill Theresa. On the basis of those threats, prosecutors are trying to prevent his release. But it appears unlikely he will be held indefinitely.

What practical advice do you offer people in show business who are worried about the threat of violence?

The most important thing is keep their addresses and schedule private. At the very least, they should use a post office box for mail delivery and should register their homes and cars in ways that are not traceable. If at all possible, they should have a professional screen their mail and keep an eye out for the type of fans that pose a threat. Whenever they are making a public appearance, they should make sure adequate precautions have been taken. Make sure that the people you work with—managers and publicity people—check with each other occasionally to see if any one fan has been contacting all of them.

Are celebrities doomed to lead completely cloistered lives?

My clients are very famous, but they all get in their cars and go shopping. They do things normally, except when they are going to announced public appearances. I don't think celebrities should be paranoid, but common sense dictates that they should manage their lives to minimize the risk of dangerous encounters.