Boston teen allegedly kills based on address

Prosecutors say a Boston teenager who was supposed to be at a Red Sox game while on a day pass from a juvenile detention facility instead stalked the streets and fatally shot another teen based solely on where he lived.

Ricardo Arias was ordered held without bail Tuesday after pleading not guilty in adult court to killing 18-year-old Alex Sierra.

The 17-year-old Arias had been in State Department of Youth Services custody because of a gun-possession charge.

Authorities say he left the baseball game early Saturday and went to the South End with a friend. They say he then asked passers-by if they lived in the Villa Victoria housing project, the home of a rival gang. When Sierra said yes, prosecutors say Arias shot him.

Sierra had no gang ties.