‘I still to this day watch behind me’ — Utah has tightened its laws on secretly planting vehicle tracking devices. But there’s a loophole for private detectives.

The call came from a blocked number, and the voice at the other end of the line wasn't one Mindi Wallenda recognized.

“You need to watch what you’re doing,” the person said. “You need to pay attention when you go places. Your ex is taking pictures of you.”

Wallenda was going through a messy divorce at the time and after the anonymous call, she started spotting her ex-husband in odd places — he’d drive by while she was at a McDonald’s or out running errands and snap photographs of her. He seemed to have an uncanny ability to find her.

It wasn’t until the anonymous caller (her ex-husband’s employee, she discovered) contacted her again and met her at her Murray home that she understood what was going on. The employee walked over to Wallenda’s black SUV, reached into the wheel well and pried loose a small box that had been magnet-fastened to the frame.

It was a GPS tracking device, and it had been pinging her every move to her ex-husband. Eight years later, Wallenda hasn’t completely shaken the feeling of being followed.

“I still to this day watch behind me,” she said. “I know every car around me.”

Wallenda’s ex-husband was charged with stalking for violating a court order that forbade him from going near her or contacting her, but there were no consequences for the private investigator who affixed the device to her car.

Cottonwood Heights Police Chief Robby Russo says Wallenda’s story illuminates a weakness in Utah’s law: With little fear of repercussion, private eyes can use vehicle trackers to help abusive or controlling exes spy on their former partners. Even in cases involving a protective order, there’s not much police can do if the private investigator claims ignorance of the court injunction, Russo said.

This state legislative session, Russo and state Rep. Marie Poulson set about tightening the statute on GPS trackers with a bill that touched off a robust debate on the little-understood world of private eyes and electronic surveillance.

On one side, Poulson and Russo said the trackers can act as weapons of control and intimidation against women who are leaving unhealthy relationships. On the other, private investigators said the devices are more often used to catch bad actors or bring peace of mind to people who feel threatened by someone.

"None of us want to scare anybody,” Michelle Palmer, legislative chairwoman and vice president of the Private Investigators Association of Utah, said in an interview.

At a national level, the law on vehicle tracking devices is thin. The U.S. Supreme Court ruled in 2012 that law enforcement must have a warrant to affix a tracking device to a person’s car, but the federal government has largely remained silent on how and when businesses or individuals can follow another person’s movements with GPS.

A number of states have stepped in to fill this void — a 2016 review by the National Conference of State Legislatures found that seven states generally forbid attaching a tracker to someone’s car without permission and another seven prohibit any use of these devices to monitor someone without consent.

But until now in Utah, there was little to prevent a person from slapping a tracking device on someone else’s car or asking a private eye to do the job for them.

“They can walk into your driveway, put this device on your car. In fact they can walk into your parking garage, place it on any of your cars. And there’s no requirement to notify you,” Russo told lawmakers during the legislative session.

And the gadgets are almost impossible for the average person to spot, he says. Some are small enough to fit in the palm of your hand and blend in when slipped into the undercarriage of a vehicle.

In some cases, the tracker comes to light during an oil change, when an auto technician finds it beneath a person’s car, he said. Other times, the devices are attached and removed without the car’s owner ever knowing they were there.

During hearings on her bill, Poulson, a Cottonwood Heights Democrat, shared with lawmakers that her daughter once had a stalker — a convicted sex offender who was confined to his home and wearing an electronic ankle bracelet. She suspects he used a vehicle tracker to monitor her whereabouts because whenever her daughter would pull into the driveway, the man would call the family home moments later.

Her bill as initially drafted would’ve made it a misdemeanor crime to place a tracking device on a car without the owner’s consent, in most cases, and private investigators would be no exception. But the measure had a rough ride through the Legislature and spent weeks pingponging between the House and Senate as lawmakers struggled to agree on how to reword the legislation.

The dispute dragged into the final day of the session, when a half dozen House and Senate legislators sat down for a spirited conference committee meeting to resolve their differences.

The final version passed by the Legislature and signed by Gov. Gary Herbert does carve out an exemption for private detectives, who can still secretly put trackers on cars if the person they’re following isn’t shielded by a protective order. The private investigator is obligated to check for any active protective orders before installing the device, the new law states.

Rep. Kim Coleman, who represented the House in the conference committee, admits the final day debate got her a little fired up and says she’s still steamed by its conclusion.

“It still boggles my mind that we would say someone who can be hired by anybody can put a tracking device on my car,” Coleman said in an interview after the session. “I don’t get the world where you say a private entity can attach their property to my property without my knowledge. ... Why that does not make everybody’s hair stand up on the back of their necks in America is just a mystery to me.”

The West Jordan Republican ended up voting for the compromise bill on the House floor but only because it was better than nothing, she says.

Palmer, owner of Corner Canyon Investigations, was satisfied with the bill’s final form, although she wishes her industry was consulted on the front end and wasn’t maligned during the legislative process.

In actuality, she said, most private investigators seldom use trackers and never give their clients access to real-time information about a person’s location. The devices are a cheaper alternative to round-the-clock physical surveillance and can come in handy during child custody disputes or when businesses want to keep track of a disgruntled former employee.

Once, she used a tracker to keep tabs on a client’s alcoholic ex-husband while he was watching the divorced couple’s children. That continued until the device pinpointed the man’s location at a bar and police found him inside drinking while his kids sat in the car.

He was arrested and full custody was awarded to the mother, Palmer said.

Sometimes, a woman who was the victim of domestic violence might use a tracker as a form of protection against an abuser, she said. Private investigators can erect a virtual “fence” around a woman’s home or workplace and alert her if the abuser crosses this invisible line.

Palmer said she and her peers reject clients who seem to have a nefarious intent.

“Those of us that value what we do, we’re helping people, not hurting people,” she said.

Sim Gill, Salt Lake County district attorney, said his office is screening a potential case against a private investigator, but he can’t recall previously prosecuting a private detective for using a GPS tracker. It’s hard to view attaching a device to a vehicle as a property crime, he said, asking whether you’d charge someone for sticking a Post-it to a car.

But he said a situation in which a person hired a private detective to circumvent a protective order would raise interesting legal questions.

“A victim of domestic violence or sexual assault or a stalking victim has every right to privacy, whether that is violated by the defendant themselves of a third party acting on behalf of the defendant,” he said.

One point repeated by the private investigators during hearings on Poulson’s bill is that they use the tracking devices to help women keep tabs on an abusive ex or stalker, not the other way around. That’s a claim Wallenda has difficulty buying.

“I don’t know any woman that is a normal mom ... who would say, ‘Oh, I need to find out where my ex is because I’m afraid of him,’” said Wallenda, who testified on Capitol Hill in support of Poulson’s original bill. “You just do your thing ... and try and stay away.”

Russo said he’s not entirely happy with the language ultimately approved by the Legislature this year. Even though private investigators would be forced to check for protective orders before attaching a device, there are still loopholes, he said. For instance, if a woman gets a court order after the tracker is put on her car, the private eye wouldn’t be required to remove it, he says.

The chief said delving into the world of private investigators even has him looking over his shoulder — and sweeping his car weekly for tracking devices.