The Los Angeles Police Department Central Traffic Division conducted a checkpoint to pass out fliers, trying to generate some new leads.
On Aug. 6, Roberto Diaz was riding his bike when he was struck at 37th Street and Maple, then dragged to Martin Luther King, Junior Boulevard and Woodlawn.
Police say Diaz was struck by the car and dragged 1,500 feet after the hit-and-run driver allegedly blew through a stop sign.
The suspect vehicle is described as a blue Honda Accord or Civic.
Diaz's sister was at the checkpoint Wednesday night. She had a tearful message for the driver:
"Can you please turn yourself in. My brother didn't deserve this," Edith Martinez said.
Diaz has undergone at least six surgeries as doctors hope to save his arm and leg.
MORE: Surveillance video shows teen being dragged by hit-and-run driver's car in South Los Angeles