Mother's testimony leads to mistrial in case of toddler's murder 01/14/2016 8:12 am PST Comments KDVR via WHO: DES MOINES, Iowa -- (WHO) -- The trial for a man accused of killing his girlfriend's toddler ended in a mistrial Wednesday. The mistrial was declared by the judge due to comments made by the child's mother, Nissa Alvarez, during testimony Wednesday morning. Joe Lopez, 26, is accused of killing 20-month-old Ruby Alvarez. Alvarez was asked about her relationships with Lopez, who had just moved in with Alvarez and her daughter a few months prior to Ruby's death. FULL STORY: Mother's testimony leads to mistrial in case of toddler's murder - WHO Waiting for your permission to load facebook comments.