christian tyrrell , 22 , was arrested wednesday on charges of murdering 2-year-old adrian langlais , the son of his girlfriend jessica langlais .
john winkler and laura martinez considered adrian 's grandparents , even though they were n't blood related to the little boy 's mother .
martinez 's son - winkler 's stepson - started dating langlais when she was six-months pregnant with adrian and they continued to babysit the toddler .