The murder case of Alexa Bartell, who was allegedly killed when three teens went on a rock-throwing spree in Jefferson County last year, is back in the spotlight this week following a series of new developments in court. Defendants Zachary Kwak, Nicholas Karol-Chik and Joseph Koenig all appeared together on Tuesday morning, May 7, for a joint motions hearing as they prepare to have three separate trials this summer…