The jury found 26-year-old Israel Mireles guilty of capital murder and rape in the death of Zane, whose birth name is Emily Sander.
Her family and friends shed tears as the verdicts came down, according to news reports.
Mireles testified that he went on the run because he was afraid authorities would blame him for her death.
Mireles fled, but had been living in a local motel where the hotel owner discovered Mireles’ room had been in a shambles and had evidence of blood spatter.
Mireles also testified that he and Zane went to the motel, had sex and drank beer.
His attorney has said another man came into the motel room and became violent after a drug deal went sour.
Mireles testified that he got into a fight with the man and left the motel.
When he returned, he says he found Zane’s body in the room, wrapped her body in a blanket, put it in his car, dumped it near the side of the road and drove to Baxter Springs to pick up his girlfriend. The two then drove to Texas and on to Mexico.
Mireles said he didn't know why he didn't call police. " I was scared," Mireles said. "I figured the first person they'd blame would be me."
Authorities later found Zane’s blood on a knife and clothes in a trash bin at his girlfriend's grandmother's house in Baxter Springs.
Zane’s body was found little more than a week after she disappeared about 50 miles from where she was allegedly last seen leaving a bar with a man matching Mireles’ description, according to witness testimony.
Mireles faces life in prison without parole — but not the death penalty — because his extradition terms forbid it.