stolen 2018 Trek

I CAME HOME AROUND 6 PM AND NOTICED THE BACK GATE LEADING INTO THE ALLEY WAS OPENED. I GLANCED OVER TO THE PORCH WHERE I KEPT MY BIKE AND SAW THAT IT AND THE HELMET THAT WAS ON THE HANDLEBARS WERE BOTH GONE. I'M NOT SURE WHAT TIME OF DAY IT WAS STOLEN, SINCE IT WAS IN THE BACKYARD LAST NIGHT. MY BIKE IS MOSTLY GREY WITH BLACK WRITING ALONG THE FRAME AND BLACK TIRES. IT WAS BRAND NEW, I HAD PURCHASED IT IN MAY FROM A TREK STORE IN AVONDALE, AZ.