President Barack Obama has signed into law a measure to create a nationwide alert system to help catch anyone who hurts, kills or makes credible threats against police officers.

The new system would be similar to the Amber Alerts used to find abducted children.

The bill is named for New York City police officers Rafael Ramos and Wenjian Liu (WEHN’-jihn loo), who were shot in Brooklyn days before Christmas by a man who later killed himself. Families of the slain officers were on hand to see Obama sign the bill in the Oval Office.

Obama says it’s important for communities to do everything possible to ensure the safety of police officers. He says the alerts could help warn officers when there is an active threat against them.

(AP)