( CNN ) -- Trayvon Martin 's parents will ask the U.S. Justice Department to review a local Florida prosecutor 's interactions with police investigating the teen 's shooting death , the family 's lawyer said . The Justice Department launched an investigation into Martin 's death on March 19 , but the family is now asking it to look for possible interference by State 's Attorney Norm Wolfinger 's office with Sanford , Florida , Police Detective Chris Serino , attorney Ben Crump said . The Martin family will send a formal request to the Justice Department Monday , Crump told CNN Sunday . Martin , 17 , was fatally shot by neighborhood watch volunteer George Zimmerman , 28 , after Zimmerman called police to report him as a `` suspicious '' person on the evening of February 26 . Zimmerman says he killed Martin in self-defense after the teen punched him and slammed his head on the sidewalk , according to an Orlando Sentinel report that was later confirmed by Sanford police . Police cited Florida 's `` stand your ground '' law , which allows people to use deadly force anywhere they feel a reasonable threat of death or serious injury , for not immediately arresting Zimmerman . Authorities have said Zimmerman was not immediately charged because there were no grounds , at the outset , to disprove his account that he 'd acted to protect himself . Martin 's family and supporters say Zimmerman , who is Hispanic , racially profiled the teen , who was black , and ignored a police dispatcher 's directive not to follow him . The killing sparked nationwide protests , including a march Saturday by civil rights luminaries , carrying `` Justice for Trayvon '' signs in a marching to the Sanford police headquarters . The Sanford police department has come under intense scrutiny for its actions following the shooting , and protesters renewed their call for the firing of police Chief Bill Lee , who stepped aside temporarily this month amid criticism . The local prosecutor also stepped aside . Gov . Rick Scott appointed a special investigator to decide if Zimmerman should be charged , cleared or if the case should be sent to the grand jury . CNN 's Vivian Kuo contributed to this report .
Family wants Martin to look for possible interference by state attorney . Family will send a formal request to the Justice Department March 19 , lawyer says . A special prosecutor is handling the case after the local prosecutor stepped aside . Police cite Sanford 's `` stand your ground '' law in not arresting Martin in the Justice Department 's death .