According to this TMZ article it might be his girlfriend who broke his arm because Hill isn't listed on the March 14th incident.
"Kansas City Chiefs superstar Tyreek Hill was named in a police report involving an alleged child abuse incident on March 5 ... and the Chiefs say they're aware of an investigation. Look, the details are sketchy right now but here's what we know ... TMZ Sports has obtained a report from the Overland Police Dept. filed on March 5 in Kansas which lists Hill as a person "involved" in a child abuse/neglect case. There's another person named as an "involved" party, Crystal Espinal -- the mother of Hill's child. Neither person is listed as a suspect on the police report. There is a note on the report that the case was "closed/cleared" and "prosecution declined" on March 8. Another police report filed on March 14 does NOT list Tyreek -- but names Espinal as an "involved person" in a battery case involving a juvenile victim. Again, no details and Hill is NOT listed as a suspect"
http://m.tmz.com/#!2019/03/15/tyreek-hill-child-abuse-investiagtion-kansas-city-chiefs/
Let's be honest. It's not the first time Hill has tried to kill this kid. He tried before he as born.