Atlanta ( CNN ) -- Autopsy results released Friday revealed that Ryan Brunn , the Georgia man who this week admitted murdering a 7-year-old girl , committed suicide by hanging himself in a prison cell , a state agency said . The Georgia Bureau of Investigation , in a news release , said the autopsy indicated that Brunn died of `` ligature hanging and the manner of death ( was ) suicide . '' The 20-year-old hung himself with his sweatshirt , investigators determined . A medical examiner did n't find any `` other significant trauma on Brunn 's body . '' `` The ongoing investigation by agents ... has not uncovered any evidence to indicate Brunn 's death was anything other than a suicide , '' the state investigative bureau said . Georgia Department of Corrections spokeswoman Kristen Stancil had said that Brunn was found unresponsive at 4:15 p.m. Thursday in his cell at Georgia Diagnostic and Classification Prison in Jackson , and was pronounced dead at a hospital at 5:37 p.m . In a Cherokee County courthouse on Tuesday , Brunn pleaded guilty to a charge of murder in the death of young Jorelys Rivera in Canton , about 40 miles north of Atlanta . He was sentenced to life in prison without the chance of parole , avoiding a potential death sentence by lethal injection . A maintenance worker at the same apartment complex where the girl lived , Brunn said in court that he devised a plan to lure Jorelys -- whom he said he 'd never talked to before -- after he found one of her skates . On December 2 , 2011 , Brunn took a picture of the skate and approached the girl with it , asking if the skate was hers . She said yes , and Brunn promised to take her to it . Instead , he took her to an empty apartment and instructed Jorelys to pull down her pants . He then put tape over her face and cut her throat with a razor . At this point , she was still alive , he told the court . Brunn said that he then took Jorelys to the bathroom and beat her to death with the skate . He said he did not have sex with the girl . The girl 's mangled body was found in a trash compactor three days after she went missing . Two days later , Brunn was arrested . He was eventually indicted on 13 counts including murder , aggravated assault , aggravated child molestation , enticing a child for indecent purposes and more . `` I 'd like to apologize for everything I 've done , and I do deserve everything that you 're about to give me , '' he said Tuesday in court . Jorelys ' father , Ricardo Galarza , told CNN en EspaÃ±ol on Thursday that news of Brunn 's death partly made him `` feel good but , on the other hand , it does n't because my daughter will never be with me again . '' `` What I wanted was for them to put him in the electric chair and burn him , '' Galarza said . `` I would have taken him there myself and prepared it , so he would burn . '' Canton Police Chief Jeff Lance `` stepped down '' on Thursday after an audit probing his department 's handling of the case , police department spokeswoman Candy Worth told CNN on Friday . The interim chief is Todd VandeZande , she and the police department 's website indicated . The audit is dated January 12 and was conducted by Louis Dekmar , police chief in LaGrange , Georgia , and president of the Commission on Accreditation for Law Enforcement Agencies . Dekmar determined in the audit that Canton police violated their own policies and accepted practices . He further contended that there was a `` clear absence of leadership by the agency head . '' Dekmar concluded that , by the time Jorelys was reported missing , she was most likely dead and it was unlikely police could have saved her . But he added that if Canton police take similar action in future cases they may `` indeed miss an opportunity to save a victim 's life . '' CNN 's John Branch and InSession 's Jessica Thill contributed to this report .
NEW : Georgia police chief steps down after audit critical of the handling of the case . Ryan Brunn hung himself with a sweatshirt in a prison cell , investigators say . A medical examiner does n't find any `` other significant trauma '' on his body . He had pleaded guilty this week to murdering 7-year-old Jorelys Rivera .