(NEXSTAR) – Last month, a victim of domestic abuse was able to alert an onlooker to her plight at a convenience store in California — all without raising the suspicions of her alleged abuser, who had accompanied her to the store.

She was able to do this through the use of a hand signal, according to police.

“It was determined that a domestic violence incident had occurred, and the victim was asking for help using hand signals behind her back,” the Alhambra Police Department later said of the Aug. 19 incident.

Police did not say which gestures the woman may have used. But organizations offering support to women and domestic violence victims have promoted the use of the “Signal for Help,” a hand gesture created by the Canadian Women’s Foundation for victims who are being monitored or cannot speak freely.

The organization originally created the gesture in the early months of the pandemic in response to an increased risk of gender-based violence between members of a quarantined household, a spokesperson for the foundation told Nexstar. (Data reviewed by a United Nations agency indicated such violence had “intensified” during that time, with studies showing that several factors — including a lack of immediate support, financial issues, alcohol abuse, etc. — were fueling upticks.)

The signal, as it was designed, could be performed in silence from a distance, over video chat, or even through a window.

“It’s a simple one-handed gesture someone can use, without leaving a digital trace, to communicate they need someone to safely check in and support them,” the Canadian Women’s Foundation writes.

Making the signal is also intended to be easy but distinctly recognizable. This gesture is made by showing an open palm, then tucking your thumb inward and closing the rest of your fingers over the thumb to “trap” it.

But knowing how to perform the signal doesn’t mean onlookers know what to do once they see it. That’s why the Canadian Women’s Foundation urges supporters to become “responders” by taking action and reaching out safely, which can mean contacting them at a private phone number or email address. The foundation offers a guide and a mini-course with more information.

Organizations including the Canadian Women’s Foundation, the Women’s Funding Network and the U.S. Department of Veterans Affairs have promoted the use of the Signal for Help, adding that onlookers should call the authorities if they believe a victim to be in immediate danger.

Arguably, however, the gesture has reached a much wider audience on TikTok, where tutorials explaining the significance and uses for the signal have been viewed millions of times. And those viewers are indeed putting that knowledge to use, helping to rescue victims.

In one such case from 2021, an abducted teen who learned about the Signal for Help on TikTok was able to alert a motorist to her predicament from the window of her abductor’s moving car. Speaking about the incident with The New York Times, Officer Gilbert Acciardo of the Laurel County Sheriff’s Office in Kentucky later said he wasn’t initially aware of the gesture, but quickly familiarized himself.

“This is probably the best thing I’ve seen come along in the 48 years I’ve been a patrol officer,” Officer Acciardo said.

Victims of domestic violence can contact the National Domestic Violence Hotline for additional support or resources by calling 1-800-799-SAFE or texting “START” to 88788. Online chat services are also available.