It's getting a lot tougher to keep a secret stash.

It's a sad but true fact of marriage: Troubled couples often try to hide money from each other, whether to spend it on extramarital mischief or keep from sharing it in a divorce. They might do anything from stashing wads of money in a safe-deposit box to setting up a secret online brokerage account to build up funds on the sly.

But however they do it, let the hiders be warned: Electronic discovery is making it a lot easier to uncover all that covert activity.

Suspicious spouses might dig around in their partners' Web-surfing history and social networks to find traces of hidden bank accounts and business deals. They might install software on home computers that records every keystroke their spouses make -- whether it's secret stock trades or cash transfers to paramours -- and use smartphone and GPS tools to show when they've been making sneaky withdrawals from ATMs.

Meanwhile, divorce lawyers and forensic experts are employing new strategies of their own. Instead of having to sift through reams of paper records to find irregularities, they're now able to use advanced search tools to analyze thousands of digital bank statements, credit-card bills and other files in the blink of an eye.

'While in the past a paper trail might be hidden by a second set of books or the shredding of documents, the trail left by files on a computer is etched onto a hard drive somewhere, just waiting to be discovered,' says Ken Altshuler, president of the American Academy of Matrimonial Lawyers.

Is it legal for spouses to use these methods to find electronic evidence? That's another matter entirely. The law is still evolving, and there are still gray areas about what practices are acceptable.

It's legal, for instance, to do a Google search on a spouse. But it's potentially illegal to hack into a spouse's personal password-protected smartphone or Facebook page, or to secretlyinstall a GPS in their car or to install keystroke monitors on somebody's computer.

There are also gray areas about what's admissible in court -- it can vary not only from state to state but also from court to court within a state. Generally, though, information that is obtained illegally is inadmissible in court.

The price of obtaining evidence illegally, of course, is potentially much higher than that. A person who uncovers information illegally could lose all credibility in court, and his or her attorney may not be able to present any evidence on that issue. On top of that, the person could go to jail, while the lawyer could face hefty fines or lose his or her license if caught using illegally obtained evidence.

Little wonder that lawyers say they advise clients to do nothing illegal. Still, they say, often angry spouses go ahead anyway, determined to get information -- and convinced that all's fair when it comes to a lying spouse. They feel that uncovering the truth is worth the risks, if they even think about the risks at all.

Even if spouses can't use the information in court, the lawyers say, the knowledge empowers them in negotiations. And once they know about the assets, they sometimes can look for legal ways to ferret out the same information.

To get an idea of just how widespreadfinancialmischief is, consider a couple of surveys. According to the National Endowment for Financial Education, 31% of U.S. adults who combined assets with a spouse or partner say they have been deceptive about money, and 58% of these adults say they hid cash from their partner or spouse.

The numbers also confirm that technology is playing a growing role in uncovering that double-dealing. In 2010, 81% of the members in the American Academy of Matrimonial Lawyers said they had seen an increase over the past five years in the use of evidence from social-networking sites. This year, 92% said that over the past three years, they have seen an increase in the number of cases using evidence taken from smartphones.

Part of the reason electronic discovery is booming is that more people are using technology to hide assets in the first place. They set up covert business deals using text messages or social networks, for instance, or figure out ways to create cash hoards online.

Paul Lewis, a data forensic expert in New York, has seen many cases where a spouse creates a PayPal account without the partner's knowledge to finance an extramarital affair. Once the account is funded, the owner can pay for hotels, jewelry, trips -- all without the partner having any knowledge of those activities.

But many spouses who think they're being clever forget one simple fact: All of that electronic activity leaves traces. Experts say many people assume they have permanently deleted an email, Facebook post or other communication -- when that's often not the case.

'Realize that any time you have an electronic device on, information can be saved and it can be later tracked,' says Michael Arkfeld, a Phoenix-based educator in the field of electronic discovery.

Sometimes, uncovering mischief just takes some basic electronic detective work. Thomas Burrage, an Albuquerque, N.M., forensic accountant, had a client who asked her husband, from whom she was getting divorced, if he'd get a pension from his company. The husband said that he wasn't sure. Mr. Burrage did a quick search on the company website and discovered the husband was in fact eligible for a large pension -- something he had hidden from his spouse for more than 14 years.

Scott Maier, a forensic accountant in East Hanover, N.J., recently searched a free public database and discovered that his client's husband owned real estate in another state. Another simple Google search discovered a client's husband had sold his company for millions of dollars when he had told his wife it had no value.

Spouses are also doing basic detective work themselves. Gordon Cruse, a San Diego-based family lawyer, has seen spouses discover hidden assets by looking through the browsing history of the family computer and finding things like visits to bank websites where the couple doesn't have an account.

Social networks offer another opportunity to do simple snooping. As people put more of their lives and careers online, it's getting much easier to find clues to secret assets that are hidden in plain sight.

In one case, the LinkedIn profile of a client's husband led to the discovery of millions in hidden assets, says Stacey Udell, a forensic accountant in Moorestown, N.J. The husband's updates showed he actively sought new clients for two businesses he hadn't disclosed, Ms. Udell says. And on one of those company's websites, his bio bragged about the profitably of the business and his engagement to his 'beautiful girlfriend.'

The husband, who had claimed he was nearly bankrupt and didn't have a girlfriend, settled with his wife soon after.

In another case, a client of Mr. Burrage's was alerted to an incriminating picture on Facebook: Her husband had been tagged in a photo by his girlfriend. The client already knew her husband was seeing other people, but the photo showed the husband and girlfriend having drinks on a beach -- while the husband was claiming poverty.

When the husband was confronted with the incriminating picture, he was speechless. 'He couldn't explain how he paid for the vacation,' Mr. Burrage says.

Some couples use more complicated -- and sometimes more legallyquestionable -- technology to uncover each other's moves. For one, there's key-logger software, which tracks everything you type on a computer.

Mr. Cruse, the San Diego family lawyer, recalls a case where a husband installed the software on a home computer to keep tabs on the wife. In California, where Mr. Cruse practices, it's illegal for a spouse to install key-logger software on the family computer to monitor the password-protected email account of a spouse.

The wife suspected her email was being monitored; she told Mr. Cruse, who had an IT expert analyze the computer. They discovered the husband himself used the computer after the software had been installed -- and recorded a visit to a secret bank account.

'He had tracked himself,' says Mr. Cruse, adding that the case was settled when the husband was confronted about the software and bank account.

Smartphones are also playing an increasingly large role in revealing hidden assets. Mr. Lewis, the data forensic expert in New York, says he recently worked on one case where the spouse enabled the 'find my phone' software on all of her family's smartphones, which lets you pinpoint the location of the phone using GPS. She quickly learned of her husband's frequent trips to an ATM, where he withdrew cash she didn't know about. Not to mention that it tracked him to a strip club, jewelry stores and various girlfriends' apartments.

In another case, a woman went on a vacation with friends and left her smartphone on the kitchen counter. Her husband suspected she was having an affair and asked Mr. Lewis to analyze the phone, which was on a family account in the husband's name. (In New York and most other states, a phone on a family plan and located within the house where both spouses reside is fair game, says Mr. Lewis.)

An examination of the text messages on the phone showed that the wife was hiding assets -- using text messages to set up drug sales.

But that was just the start of the surprises. Information on the phone showed she was living a double life, with multiple boyfriends and sex clubs. The harshest finding was that she had hired a hit man to kill her husband while she was away on vacation.

'We prevented a homicide,' Mr. Lewis says.

For some suspicious spouses, the GPS in their vehicle is another detective tool. Mr. Lewis has seen spouses swap out their GPS with a nearly identical model that takes pictures of all the car's destinations -- such as trips to a bank where the spouse has a secret account. In some cases, the GPS also let spouses view the vehicle's location live on a computer or smartphone, or take pictures of who's riding in the front seat.

Another big change is taking place in how experts sift through records to find clues to financial mischief. In the past, says Vista, Calif., family lawyer James Hennenhoefer, lawyers might have to pore over thousands of paper bank statements, credit-card and phone bills with a team of assistants, looking for discrepancies or odd transactions.

Today, Mr. Hennenhoefer says, he can do things like scan through thousands of emails in a matter of milliseconds to help find funds. In one recent case, he searched the email of his client's husband, looking for the name of the husband's girlfriend. The hard drive was on a computer in the house that was not password protected, which made the resultant data admissible, Mr. Hennenhoefer says.

The search turned up a note detailing the transfer of $100,000 to a Swiss bank account for the girlfriend's benefit. 'He thought we'd never find it,' says Mr. Hennenhoefer.

For all of the technology that's out there, though, some experts recommendtaking a very basic first step when one spouse suspects another of financial mischief. Instead of immediately snooping around for evidence of misdeeds or turning to an outside pro to do a thorough check, they say it's better to simply approach the spouse about the suspicions, and then try to talk things through.

Mr. Lewis, the data forensic expert in New York, thinks a lot of trouble could be avoided 'if spouses had more open and honest communication.'