The Maricopa County Attorney's Office decided yesterday that it will try Braden Matthew Rockriver as an adult for allegedly murdering his 18-year-old girlfriend's mother earlier this week.

Rockriver's not exactly an adult, though -- he's 16.

According to Mesa police, Rockriver made plans to steal his father's gun and kill either himself, his girlfriend, or end both their lives in a murder/suicide. However, his girlfriend's mother, 42-year-old Denna Strebe, got in the way.

Rockriver, police say, broke into the Strebe's garage, waited for someone to open a door leading into the house, and then forced his way in when Denna Strebe opened the door.

After a brief scuffle, the gun went off. The bullet hit Strebe in the head, killing her.

Rockriver may be 16, but his alleged crime is pretty heinous -- as we mentioned, police say he planned to kill someone hours before he carried out his murderous plot. That's called premeditation.

See our story on Strebe's murder here.

If you ask us -- and County Attorney Bill Montgomery -- Rockriver fits the bill for a juvenile who should be tried as an adult. But we want to know what you think: should Rockriver be tried as an adult?

Cast your vote below.