BOISE, Idaho AP – When police officer Darryll Dowell is on patrol in the southwestern Idaho city of Nampa, he’ll pull up at a stoplight and usually start casing the vehicle. Nowadays, his eyes will also focus on the driver’s arms, as he tries to search for a plump, bouncy vein.

“I was looking at people’s arms and hands, thinking, ‘I could draw from that,’” Dowell said.