When a woman went missing from her home in Sugarmill Woods, Florida last week, her family called the police. She had only been missing for two hours—but she was an elderly woman suffering from dementia.

Dementia patients wandering from their homes is a common and extremely dangerous side effect of the disease. The Alzheimer’s Association reports that 60 percent of patients will wander—and if they’re not found within 24 hours, they have a high likelihood of risking injury or death.

“Anyone who has memory problems and is able to walk is at risk for wandering. Even in the early stages of dementia, a person can become disoriented or confused for a period of time,” the site reads. “It’s important to plan ahead for this type of situation.”

This family took a little-known precaution that ended up being a life-saver.

When officers from the Citrus County Sheriff’s Office arrived on the scene, they brought with them a K-9 detection dog named Ally.

The dog was there to track down the elderly woman by her scent. Luckily, the family had just the thing and handed the officers a sealed jar.

Facebook: Citrus County Sheriff’s Office

It was the woman’s scent, perfectly preserved. The family had prepared the kit two years ago in the event of this kind of emergency by applying a cotton swab to her armpit and sealing it the special jar.

The kit was from a local organization called Find-M’ Friends, Inc. In addition to selling the kits, they provide training for bloodhounds to detect missing people and encourage their use in investigations.

While bloodhounds are often given the missing person’s scent via an item of clothing, these jars ensure the scent won’t be contaminated with other odors or fade over time. The sealed kits can preserve the scent for up to seven years.

Facebook: Find-M’ Friends, Inc.

Once Ally got a whiff of the scent, the dog was able to track down the woman—in less than five minutes!

She even got a tasty treat as a reward for bringing her home safely:

Facebook: Citrus County Sheriff’s Office

The Alzheimer’s Association provides a useful list of how to prevent dementia patients from wandering and what to do if someone is missing. But in a seriously dangerous situation, the scent preservation kits may provide additional peace of mind and be a real life-saver in an emergency.

And they’re not just for families of dementia patients—these kits can be useful for tracking down young children, especially children with autism who are at a higher risk of running off.

Find-M’ Friends provides kits to the Florida area, but you can still contact the company or your local law enforcement for information on how to have a scent preservation jar prepared for your loved one.