-- Parents freaked out by the frightening stories of nannies neglecting their charges -- or worse -- are taking what some might call extreme measures when it comes to vetting caretakers for their kids.
The instances of people hiring professional investigators to spy on their kids' babysitters is "absolutely" on the rise, according to Tom Ruskin, head of CMP Group Investigations.
"We are getting more calls now than ever before," Ruskin told ABC News. "It's an extreme step. You're basically saying I don't really trust this person who is with my children and I want to know what's happening, I want to know firsthand. You have to feel comfortable with this person who is basically joining your family as an outsider."
ABC News followed a private investigator from Ruskin's firm as he trailed the potential sitter for the four-month-old baby of a new mom.
"It's very hard to find somebody you can trust," the mom, whose identity is not being revealed, told ABC News. "I'm a first-time mom, going back to work, I need to make sure I'm going to be able to concentrate at work. I don't want to worry about what's going on at home. I want to make sure I'm going to hire somebody who is responsible enough."
Ruskin assured the new mom that if the investigator spotted anything questionable, he'd be in touch immediately.
While one of Ruskin's private investigators once found a stroller left unattended on the street as the nanny shopped in a store, "nanny distraction" is actually quite common, said Ruskin. The "nanny is either talking to other nannies, texting or on the phone, not paying attention to the children," he added.
With the use of nanny cams -- and the knowledge of their existence -- so commonplace, what's going on outside the home may be most telling, said Christine Irwin, founder and moderator of the popular parenting Facebook page UES Mommas.
The page is popular for moms looking for advice on everything from organic formula to kids music classes. Another kind of posting has become increasingly popular: moms taking and posting photos of nannies or babysitters they perceive to be behaving badly.
Irwin is quick to point out, however, that "99 percent" of nannies are good ones. But she says the so-called mom spies are trying to alert other moms about "unfortunate situations" when they occur.
"I think that we're all in this for the same thing, the love of a child. [A mom] sees another child and she sees something that's wrong and she looks at her own child and she says if this was my nanny, I'd want to know about this," Irwin said.
For the mom that used CMP's services, the findings were positive. The investigator gave the sitter a perfect score.
"Once you left she began her walk, up and down the hills, was really good at crossing the street," he told the mom. "When wind blew she checked the comforter. This is someone you'd want to hire."
"There's nothing too extreme to make sure your child is safe," the mom said.
For those who can't afford a private investigator, Ruskin suggests parents leave cameras in the house on at all times. "After awhile," he said, "everyone forgets they're there and the real behavior shows through." He also suggested parents act as their own spies, showing up unannounced at places they know that child will be with the sitter, and watching for a few minutes before approaching.
His bottom line: "If your gut is telling you something is wrong, 99 percent of the time, it is."