Pennsylvania Attorney General  Kathleen Kane and Philadelphia Mayor Michael Nutter joined top prosecutors Monday in San Francisco and New York in a nationwide initiative to thwart smartphone thefts by rendering the devices useless after a robbery, the Times Leader reports.

The initiative, Secure Our Smartphones, brought New York Attorney General Eric Schneiderman to Philadelphia to make the announcement with Nutter and Kane. The group was begun in June by Schneiderman and San Francisco District Attorney George Gascon with the hope of successfully pressuring the smartphone industry to develop a technological solution, such as a “kill switch” for stolen phones, that would make smartphones inoperable after they are stolen.

They say such a safety switch would stop the robberies that are feeding a massive and lucrative secondary market for stolen devices, the article reports.

Last year, lost or stolen cellphones cost consumers more than $30 billion last year. According to a report released by AAA in August, Philadelphia is ranked the number one city for smartphone theft in the United States. The Philadelphia Police Department reported 516 instances of personal theft from the beginning of 2013, up three percent from last year. On average 39 phones were stolen per month on the SEPTA mass-transit system in 2012.

According to the Federal Trade Commission, cellphone robberies make up 30-40 percent of all robberies in major U.S. cities. 

Want to join the Secure Our Smartphones initiative? You can sign the petition here