Carrying a small box and what looked like a miniature TV antenna, Minneapolis fire Capt. Jim Hart listened for beeps that would tell him whether he was walking in the right direction.
"Jason, do you hear me?"
Jason is Minneapolis firefighter Jason Oxford. He was hiding somewhere at the department's Emergency Operations and Training Facility, maybe crouching behind one of the many fire rigs parked on the grounds.
As Hart approached a trailer parked under a canopy of trees, the signal got stronger.
"I think Jason — or Billy, whoever we're looking for — is right around the corner," Hart said. "Come on out, sir!"
Jason Oxford emerged into view, wearing something resembling a hospital bracelet with a plastic pod attached. The band of the bracelet contains a unique number assigned to the wearer. The antenna Hart used to track the bracelet can be mounted on fire trucks and helicopters.
The bracelet and the antenna are part of a system called SafetyNet, which Minneapolis will soon join St. Paul in using. It can help emergency responders find missing children and adults with cognitive disabilities like autism or Alzheimer's disease.
Minneapolis resident Tony Farah said he'll be the first to sign up. He has an 11-year-old son with autism.
"You see, living with fear of wandering is very scary," Farah said. "We don't have to live with that anymore after today. We lost him for five minutes, a while back, and it felt like five years."
Praise for the system also came from Jonah Weinberg of the Autism Society of Minnesota. Weinberg said that the prevalence of autism in Minnesota has increased significantly over the last 40 years, and that the system will give more families like Farah's peace of mind.
The city of St. Paul has been using SafetyNet for five years. Fire Capt. Keith Golden said the system was recently expanded to include all of Ramsey County. Nearly 70 people are enrolled in the program, he said.
"And since the February rollout for the entirety of Ramsey County, we've probably had 20 successful rescues of people that wandered," he said.
The field operations manager of SafetyNet Tracking Systems, Ralph Poland, said that to enroll in the program can cost several hundred dollars. But other cities have found ways to make the program affordable for low-income people, he said, and there's a bill in Congress that would provide federal funds to cities like Minneapolis to make the bracelets free of charge.
"So I would ask everybody to contact your local state reps and senators and ask them to vote in favor of this bill," he said.
Minneapolis officials said 13 other U.S. cities, including St. Paul, are using the SafetyNet system.