Comedian Chris Rock once made a statement that private investigator David Cohen says he has considered framing on his desk: "Men are as loyal as their options."

Cohen founded his own private investigation firm, Investigative Resources of Texas, in 1994 after assisting collection agencies in their pursuit of big debts and in worldwide efforts to locate military deserters. He has abundant experience in insurance fraud and is a highly paid expert witness in different kinds of trials, but he considers one field a specialty: matrimonial investigation. If you're cheating on your spouse, he or she can hire Cohen to track your lying ass around the city, state, country and world to document evidence of adultery for divorce cases.

"Texas is going into its fifth year leading the nation in divorce rates," he says. "Dallas-Fort Worth is right up there. North Richland Hills, Addison, the Mid-Cities--they're all hotbeds for adultery. Highland Park is big, too. I've had some very rich, very eccentric clients from there.

"Generally speaking," he continues, "we have a stronger economy than the rest of the country. We have loose income brackets, discretionary income, people working for large commissions. All those create incentives to stray."

Marriages that turn stale often share some common traits: Both partners are working professionals with a combined income of $70-$120,000, children and a mortgage. And incidentally, contrary to the legions of spurned women pouring out their tales on daytime talk shows, Cohen says that in his experience, wives cheat on their husbands as often as vice versa. People choose to continue a troubled marriage either because they don't want to admit it's hopeless--and seek solace in other arms--or they simply crave both the stability of the institution and some variety on the side. They rarely travel very far for that extra bit: He estimates that in 80 percent of the investigations he handles, the cheater is having an affair with a co-worker. Perhaps strangest of all, that co-worker usually bears a strong physical resemblance to the spouse being cuckolded.

"If you suspect your spouse is cheating, then you're usually right," Cohen notes. "We're the only P.I. firm in Dallas I know of that does hard advertising. I have ads in topless clubs, health clubs, upscale restaurants. Imagine you're a guy who's worried about his wife. You have a couple drinks at a club, you walk into the rest room, and above the urinal there's an ad with a picture of a woman getting into a car and the line, This is your wife...but whose car is she getting into?' It plants a seed."

Once that seed is planted, and Cohen is hired, he or an assistant spends anywhere from 3 to 5 days a week for three weeks--sometimes totaling 12 to 15 separate periods of surveillance--to document what the courts call "a pattern of habit." Adulterers meet at restaurants or bars far outside their typical social circle, or are viewed entering and leaving each other's homes during odd hours. Cohen is always nearby--waiting in a car, or just a few tables away--to catch on digital video images of lovers holding hands, kissing, touching one another on the bottom. Sometimes husbands tryst with other men, wives with other women, but no matter the situation, Cohen halts his efforts after the couple departs a public space; while adultery itself is not illegal in Texas, spying on and taping someone in a private residence definitely is.

Paranoia runs in all directions: Cohen confirms he's been tapped for countersurveillance, in which spouses believe their husband or wife is having them followed and want him to prove it. All snickering aside, "I believe cheating on a spouse is morally and ethically wrong," he says. "It's very destructive. It wreaks hell psychologically on men and women. There are times when I've charged clients for counseling, because they spend hours and hours going over their stories, wondering what they did wrong."

Cohen's advice? "If you don't want to be married, get out. Otherwise, keep it in your pants. It saves everyone a lot of trouble."

Investigative Resources of Texas can be reached at 877-285-9519.

For years Maria Frenkel couldn't talk about why she launched her own business. Her reasons for doing it were too personal, and if asked she would simply say, "I wanted to be able to help people." Only recently has she felt comfortable explaining why she started Crime Scene Clean-Up Services of Texas.

In the spring of 1996, Frenkel, then 37 years old, was pregnant with her first child. One morning, as she sat on her bed, putting on makeup, she felt something peculiar. "It was like an electric shock that was moving up toward my navel," she says. "And then I started feeling back pains. And I thought, 'What the heck is wrong?' I didn't know what was happening until I started bleeding.

"When I came home from the hospital, I was the one who had to do the cleanup. So I spent a lot of time praying about what to do to help other people who were in similar situations."

Thus from the umber stains of that stillbirth years ago sprang Frenkel's new business. She incorporated Crime Scene Clean-Up Services that same year. She says she went door to door, offering her services to people in whose homes and apartments and places of business had occurred all manner of messy, unspeakable tragedies. Teeth embedded in walls. Puddles of blood on Berber carpet. A bathroom shower raining on a dead man's face for two weeks.

She can now talk about her own reasons for getting into the business back then, but Frenkel closely guards the details of her work today. She has cleaned up the physical aftermath of some of the most publicized deaths in the area, but the emotional mess left by these incidents, some of them recent, can't be carted off in red bags for incineration. She'd prefer the families involved not have to read about any of it here.

One case she will discuss, though. About a year ago Frenkel got a call about a situation in an Oak Cliff apartment (she and her regular team of five assistants are always on call). So she drove there in her unmarked car with her tools and solvents. She pulled on a disposable white body suit and strapped on a particulate respirator. Plastic visor to protect the eyes. All mucus membranes covered. And Frenkel went in to deal with someone else's mess.

Seems a woman had decided to go out of town for an extended period, and she had decided, in the interest of convenience presumably, to leave five dogs in her two-bedroom apartment. "And these were not small dogs," Frenkel says. "We're talking big dogs. She left huge tubs of water and food for them. Long story short, the dogs ganged up and killed one of the dogs. Another dog died, I don't know how. The other three got trapped in the bathroom, very small bathroom, and chewed through the hot water line. The hot water was running the entire time. One of the dogs was actually boiled to death. It was a horrible, horrible situation."

Space prevents a full recounting of how difficult the entry was because of water pressure against the bathroom door or how hazardous the flea infestation had grown or even how quickly the dog owner, upon returning to town, found herself behind bars. But two animals did survive. What was left of the other three went into the red bags and the incinerator. Such material is handled like medical waste, and its disposal is regulated by the state. Frenkel contracts with another outfit to haul it off.

Frenkel handles about 70 cases every year. Unfortunately, she regularly turns away work because she's too busy. Since she started Crime Scene Clean-Up services, other cleanup concerns have entered the industry. Some have endured, but most have moved on because, according to Frenkel, they didn't understand "it's not a pleasant thing to do." This is called an understatement.

"The only thing that keeps me going, that keeps me from burning out, is that I do a lot of praying," she says. "We pray, and we fast. You have to pray. You can't do it without God. You just can't do it. You see things that people do to each other that are just horrendous. I can't do it apart from the Lord. I really can't."