A suburban Dallas teenager has pleaded guilty to plotting an Islamic State group-inspired mass shooting at a North Texas mall. A state judge sentenced Matin Azizi-Yarand to 20 years in prison Monday for solicitation of capital murder and making a terroristic threat, state and federal prosecutors announced. Azizi-Yarand was arrested last May for plotting to shoot civilians and police at a Frisco mall in a rampage authorities said he was timing to coincide with Ramadan. The then-high school student had been recruiting others to participate in the shooting and planned to explain it with the release of a "Message to America," according to prosecutors. He spent more than $1,400 buying weapons and tactical gear, and had been conducting surveillance of the mall.