Dad is identified as MANUAL A. LOPEZ.
http://articles.chicagotribune.com/2012-12-24/news/chi-chicago-crime-child-abuse_1_child-abuse-suspicious-injuries-jimmie-whitelow
$100K bail for NW Side father charged with child abuse of son
December 24, 2012|By Rosemary Regina Sobol | Tribune reporter
A judge set bail at $100,000 today for a 20-year-old man accused of silencing his 4-month-old son's crying by pulling on the infant's leg until hearing a "popping noise" in the baby’s knee, authorities said.
Manual A. Lopez, 20, of the 4900 block of West Oakdale Avenue in the Cragin neighborhood, was charged Sunday afternoon with two counts of felony aggravated battery to a child, police said. Lopez is scheduled to appear in court Monday.