FORT WORTH, Texas — A Tarrant County jury has handed down a maximum sentence to the 16-year-old who opened fire at Arlington’s Lamar High School in March, killing one classmate. The jurors in Juvenile Court deliberated for about an hour before reaching the verdict Thursday afternoon, which will send the teenage defendant to prison for 40 years. He’ll begin serving his sentence at a juvenile facility and could later be transferred to an adult prison. The teen had no visible reaction to his sentence. He will not be paroled for at least 10 years. He will have a hearing before his 19th birthday to...