It was an article in Cosmopolitan magazine about hidden cameras, according to the woman’s attorney, that got her thinking about the smoke alarm inside her Chevy Chase apartment — the one over her bed, the one allegedly put there by her landlord.

She and her boyfriend examined the device. What they found, police say, started an investigation that has the landlord facing a March 4 trial in Montgomery County District Court on charges of secretly recording three tenants while they were nude or engaged in intimate acts with their boyfriends.

The landlord, Dennis Alan Van Dusen, a 63-year-old lawyer who holds graduate degrees from Harvard University, is also being sued by two of the women and one of their boyfriends, who accuse him of invasion of privacy. “My clients have been traumatized by this,” said Donna McBride, an attorney for a tenant and a boyfriend.

Van Dusen declined to comment. His attorney in the criminal matter, Samuel Delgado, stressed that Van Dusen is presumed innocent of the allegations against him. “I intend to look at all the evidence, pick it apart piece by piece, and hopefully vindicate him,” Delgado said.

A.P. Pishevar, an attorney for Van Dusen in the civil ligation, described his client as “a good man who has served his country as a retired Marine. These accusations are false and defamatory and will be challenged in a court of law.”

The case surfaced amid a string of reported cyber-peeping incidents and at a time when cameras are getting smaller, more powerful and less expensive.

“Manufacturing is up, prices are down and demand is growing,” said Michael Peros of, which sells the devices. “It’s kind of like anything in life. It can be used in a good way, or it can be used in a bad way.”

Meanwhile, in Manassas

This month, a Manassas homeowner allegedly positioned a video camera about the size of a cellphone in his bathroom — specifically among a basket of toiletries — during a Super Bowl party, according to Prince William County police.

One of the guests discovered it, leading to charges of “unlawful filming of another” against Philip Caplinger, 46, police said. Caplinger declined to comment.

In Howard County, a man was charged after appearing in one of his own recordings, according to authorities.

Michael Stephen McKenny, 42, who is scheduled to go to trial May 7, allegedly broke into a condominium, hid a Recluse Black Box video camera and captured images of two women in various stages of undress, according to Howard County court records.

Police say McKenny slipped back into the condominium several times, changing the position of the camera to capture images in two bedrooms and at least one bathroom. Police tracked Mc­Kenny down after confiscating the camera, watching the video, and seeing several images of him positioning the device, according to authorities. McKenny’s attorney, David Zwanetz, declined to comment.

Today’s tiny video and audio recorders, which can be hidden in smoke alarms, clock radios and even calculators, can sell for as little as $49, plus about $35 for the memory card, Peros said. The devices, equipped with motion sensors and tiny batteries, can capture a week’s worth of video and audio. That kind of technology five years ago, he said, would have cost about $5,000. Ten years ago, the price would have exceeded $25,000.

About 15 percent of his firm’s cyber- and bug-sweeping practice, Peros said, involves tracking down peeping-Tom cameras.

In the Chevy Chase case, Van Dusen was renting out three rooms in his home, a blue-gray house on tree-lined Ridgewood Avenue, about one mile north of the District, according to police reports and court records. Two of the rooms are on an upper level, and the other is in the basement. Everyone shared the house’s common areas, according to police reports.

In October 2012, a tenant in the basement became concerned about the smoke alarm above her bed.

“Whenever the power would go out, all the smoke detectors on her level would beep, but the one above her bed did not,” according to Montgomery police documents.

The tenant said she and her boyfriend then examined the smoke detector and found video-recording equipment and wires leading back into the ceiling. In the early morning of Oct. 13, she called police, and two officers went to her apartment and took photographs of the device, according to police reports.

Police later confiscated Van Dusen’s laptop computer and two hard drives from his room in the house, according to a detective’s affidavit filed in court. An examination of the equipment found “sexually/nude videos” of the three tenants and their boyfriends, according to the affidavit. The videos also revealed that Van Dusen had put “hidden surveillance devices in each of the renters’ rooms,” the affidavit states.

Police charged Van Dusen with seven counts of visual surveillance without consent, seven counts of using a camera without consent for “prurient intent” and one count of placement of a surreptitious surveillance device, according to court records. Records do not indicate that any of the alleged video images were posted on the Internet.

In an interview Friday, one of the tenants who is suing said that, at first, she couldn’t believe the allegations because nothing seemed out of the ordinary about Van Dusen. Then the police called her to a station and showed her videos that she said were clearly recorded in her upstairs room.

‘Completely shocked’

“I was completely shocked,” said the woman, 27, who works at a law firm in Virginia and asked not to be named. “I couldn’t sleep for days. I could barely eat.”

The tenant said she thinks there were at least two hidden cameras in her room — one in the ceiling, possibly in a smoke detector, and one in a wall. The images appeared to go back at least a year, she said. She wondered whether Van Dusen had been nice to her because he felt guilty. “Now I’m thinking that he was too nice,” she said.

The lawsuits allege that on Oct. 14, the day after police officers went to the house, Van Dusen sent text messages to two tenants. “I am willing to discuss settlement before you make a claim but not afterward,” the text messages allegedly said. “Best to communicate by email or txt.”

Jennifer Jenkins contributed to this report.