If you have children old enough to use the Internet, hopefully you've warned them of the dangers of sharing their personal information online. But what if you're the one sharing personal information?

How can you know whether the person behind a personal ad, or at the other end of an e-mail is who they pretend to be? Are you providing perfect strangers your phone number, address or other details of your personal life?

What if the person you're giving that information to is a stalker, a sexual predator or worse? How would you know? Several local women have learned the hard way that sometimes you don't know, and they have become victims of a man whose tactics have exposed at least one woman and her family to very real danger.

In the course of gathering information for a story about this man, I also became his victim. Although I am no longer the lead reporter on the Times-Union's story about this man, which is still being developed, Lt. William Gaden of the Clay County Sheriff's Office has asked me to write a public service announcement warning you of the dangers you may unwittingly be exposing yourself and your loved ones to.

Be careful out there

I'm not going to identify any of the victims here. The one's I'll tell you about, I'll just call Iris, Daisy and Rose. Although at least four different sheriff's offices in Northeast Florida, plus the Florida Department of Law Enforcement and the State Attorney's Office's prosecutor specializing in cyber-crimes are all aware of the man who is harassing these women —and me — he remains at large.

These women are not the only victims — I've talked to many others, including women out of state who are terrified of this man.

Iris met him in the brick and mortar world – not online – but when she pushed him from her life, the electronic harassment began. She says he was charming at first, but she discovered that almost everything he'd told her about himself was a lie, including his name.

He also claimed to be wealthy and said he was carrying loads of cash, but never paid for anything with cash. My experience has shown me that many con men pretend to be wealthy to get their victims to feel less anxiety over protecting their own money. Iris says he took financial advantage of her and that she now worries he knows enough about her to steal her identity – a fear echoed by police.

When she told him she didn't want to see him again, he began sending her harassing e-mails. "If I had a nickel for every lie you've told me" he wrote in one — an ironic line that he has used on almost every victim.

Daisy responded to a personal ad from a man on Craigslist, a national classified advertising Web site with a local page dedicated to Jacksonville and the surrounding area, and began exchanging e-mails with this man.

At first she says she was cautious about the amount of information she gave him, but says he seemed in no rush to meet, so over a period of several weeks he gained her confidence and her caution gradually disappeared.

She says he was charming – I'd argue that all good con men are – and although he stood her up on their first date and blamed her for it, she agreed again to meet him. She says they met at a restaurant where he ordered an expensive meal and she ate only a salad. At the end of the meal he excused himself, saying he needed to retrieve something from his car.

He never returned.

She was forced to pay for his meal, and says that before she could get home he began harassing her, sending e-mails pretending he'd sent someone else in his stead for the dinner, and then denigrating her with vile insults.

After she sent him several e-mails demanding that he stop harassing her, which he ignored, he replied with an apology followed by a post script asking if she enjoyed having sex with animals and asking if she'd like to have sex with his dog.

Like Iris, Daisy got off easy.

Rose wasn't so lucky. She also met him via a personal ad on Craigslist, and also says she was cautious at first but finally agreed to meet this man. They met at a local fast food franchise.

She said he seemed friendly, but that he was "full of it," and overly generous with his compliments. She didn't get stuck with a bill – neither of them ate anything – but as they were leaving, she said he saw what kind of car she drove.

Later, the two of them planned a day trip together, along with her children. Although she spoke to the man the night before they were to leave, he didn't show up the next morning. She went alone, but when she returned she sent him an e-mail to let him know she no longer wanted to see him.

He apparently didn't like being rejected. He began sending a series of insulting e-mails eerily similar to the ones he sent Daisy and Iris. He also sent Rose an e-mail with racist undertones in which he told her that she and her children would be killed one after another if they went somewhere that he knew they were planning to go.

Rose says she became worried that he could trace her e-mails back to her home address so she went to the library to use a public computer to tell him to stop harassing her. He immediately traced her e-mails back to the library and told her so. Terrified, she told the librarian, who called police.

Within 24 hours he posted an ad on Craigslist in which he impersonated Rose — offering mother/daughter sex. Rose's daughter is a minor. He also posted Rose's home telephone number.

Immediately, Rose began receiving phone calls from people wanting to have sex with her and her daughter. "Hundreds and hundreds of calls" came in, according to Rose. She says she called police again. According to Rose, a female officer arrived and began answering her phone, "Clay County Sheriff's Office, how may I help you?"

Rose says some of the callers were very disappointed to discover the offer wasn't real. She said some began offering money and others became angry. Someone rang her doorbell at 1:15 a.m. the following morning. Rose believes it was someone who traced her home address using the number posted in the ad — someone who desperately wanted to have sex with her and her daughter and who wasn't afraid to risk jail for the opportunity.

My cautionary tale

I discovered this story the way most reporters discover stories like this – on accident. One of his victims is an acquaintance of mine, and when she talked of her new "Prince Charming" – describing him as a man she'd met on the Internet who had tons of money – I was immediately skeptical.

I suspected he was a con man and immediately began gathering information about him. I took photos of him and his car, including his license plates. I contacted police agencies all over Northeast Florida to find out if they were looking for him or had any open investigations that he might be a part of.

Shortly afterward someone directed me to an ad on Craigslist in which a woman was complaining of being left holding the tab in a restaurant. I responded to her ad and encouraged her to contact police. I believed he committed theft of services when he walked out of the restaurant, and police have agreed.

This became a recurring theme. Women would post ads and I would respond, asking for information and encouraging them to contact police. Sometimes the women seemed embarrassed to have been taken in – too embarrassed to contact police.

After a while, I put this man's information in a folder and filed it, thinking that if he ever got arrested I would have a great story with a photo fit for the front page of the Florida Times-Union.

Two weeks later another woman ran an ad saying this man had done her wrong. I responded.

After a short e-mail exchange I was able to determine that this wasn't a woman at all — it was actually this man impersonating a woman, apparently trying to discover what women were saying about him, and whom they were saying it to.

A series of similar ads appeared in following days. I responded to them all, asking for details and encouraging them to contact police. My contact information was on the bottom of each e-mail I sent, so every person who received e-mail from me had my contact info — including the bad guy.

The following week, he posted an ad impersonating me. In it he asked women to contact him with their experiences, and promised that if they'd provide their contact information he would pass it on to police.

Because I feared that by impersonating me he might be able to get women who earlier had been careful not to share personal information to do so, and possibly put themselves in danger, I contacted police and filed a complaint.

Since then he has impersonated me several times. He has also posted an ad pretending to be a woman who had been on a date with me, titled Beware: Mark Pettus. In it, this "woman" claimed I'd taken her to dinner and left her holding the tab. He has since posted an ad impersonating me seeking a dinner companion, using personal information about me that is available on my personal Web site. He signed it Mark.

Do as I say, not as I do

When I send e-mail to someone, I cannot be anonymous — I have to make clear who I am and why I'm seeking the information. I'm a reporter, and we shine light in dark places, so hiding in the shadows isn't normally part of the job.

In addition to working for a large newspaper, I'm also a novelist and a freelance photographer. For those businesses to thrive, I have to be accessible – on the Web and elsewhere. Public exposure is a necessary part of what I do.

But for most people, public exposure on the Internet isn't necessary and may put you in danger.

To protect yourself:

-Never share your personal information with someone you don't know.

-If you're responding to a personal ad, or feel you must give a stranger your phone number for some other reason, use a pre-paid cell phone.

-Do not use an e-mail address that contains personal information. Do not respond to strangers with an e-mail that contains any part of your name – a stalker could use it to track you down.

-Do not lower your guard because the other person seems "nice." A con man who isn't nice wouldn't be much of a con man.

-Just because they share personal information with you, don't assume it is safe to share your info with them. Stalkers and con men concoct elaborate covers. The man who's stalking the women in this story gave each of them a phone number, which turned out to be an anonymous voice mail service in Tennessee. When he called them the number always showed up as "private."

-Check out people before you share any personal information with them. Stick with first names until you've had an opportunity to validate anything the other person tells you about him or her self.

-If you're going to meet a stranger, even one you've corresponded with for a long time; do so only in a well-lit public space.

-Make notes on their appearance. Pay attention to inconsistencies in the other person's stories. Also pay attention to your own instincts. If you feel as though something is wrong, you're probably right — get away from that person as fast as you can.

If you ever feel unsafe, call police.

Sgt. Chuck Mulligan with the St. Johns County Sheriff's Office recommends that if you discover you've become involved with someone who isn't what they appeared to be, you should immediately break contact, change your locks, inventory your valuables — including check books and credit cards, and let police know.

If you become a victim
Call the police if you've become the victim of a cyber-stalker or any other crime.

Save all e-mails between you and the stalker. Save copies of any ads the stalker has posted about you. If you have the stalker's e-mail address, do not ask his e-mail provider to shut down the address. Yahoo! and other providers will do so but by keeping the address active you may help law enforcement track down the offender.

Smaller police agencies aren't always well versed in the laws that govern activity over the Internet, but every sheriff's office in Northeast Florida is willing to pursue a cyber-stalker. You may have to make several repeated calls and file several complaints before police will feel like they have enough information to prosecute, but if you make the calls and file the complaints, they will. Save everything.

If the stalker is crossing jurisdictional lines, contact the Florida Department of Law Enforcement. They have special agents trained in dealing with cyber crimes. FDLE also has resources to help track down cyber-criminals who use spoofed e-mails and IP addresses. Special Agent Molly Akin is participating in the investigation of the serial stalker who has been terrorizing women across the area.

If the stalker posts an ad about you on a Web site, contact the site and ask them to take the ad down (after you've saved a copy) and to send you any information they have about the person posting the ad. Craigslist is very good about complying.

Ask the court grant an injunction barring the stalker from contacting you. Once an injunction is granted, any contact — including electronic contact — is a felony, and law enforcement will move quickly to jail the suspect.

Contact the Florida Times-Union. The paper is conducting an ongoing investigation into the prevalence of cyber-stalkers operating locally and into how local law enforcement agencies deal with those cyber-stalkers.

If you have had a bad experience with any cyber-stalker we'd like to hear from you.
If you have any information about the man who has stalked the women in this story and who continues to impersonate and harass me, let us know.

He is 6'2" tall, weighs 220 lbs, and has green eyes and brown hair, usually worn in a ponytail. He usually drives a white Lincoln Towncar with a blue cloth top. He may or may not have facial hair. He is likely a transient, moving from hotel to hotel – he prefers "courtyard" or "express" type lodgings, but may be living with a woman or may have acquired more permanent lodgings. He's been tied to lodgings in Clay County, Southside and possibly Ponte Vedra.

Although some of the things this man has done are reminiscent of adolescent pranks, police say he may be dangerous. They have asked me not to confront him, and you shouldn't either. Both Sgt. Mulligan with the St. Johns Sheriff's Office and Lt. William Gaden with the Clay County Sheriff's office have said the man's behavior indicates he may believe he is smarter than everyone else — including police. Mulligan compared his personality traits to those of Justin Barber, the man convicted last year of murdering his wife on a St. Johns County beach.

If you know anything about this man, call the newsroom – or police.