A Columbus man has been sentenced to life in prison after being convicted of causing injuries to his infant son that led to the child's death 10 months later. 31-year-old Johnnie Crockett the third was convicted this week of causing severe injuries to 8-month-old Iszaac Crockett in February 2012. Prosecutors say the elder Crockett was babysitting and was the only adult home with the child at the time when the injuries consistent with shaken-baby syndrome were sustained.