Massey's family has publicly called for Campbell to step down.
Sangamon County Sheriff Jack Campbell, who was responsible for hiring Sean Grayson, the former deputy who fatally shot Sonya Massey last month, told ABC News in an interview Thursday that he is "horrified" following the incident. He also stood by his department's vetting process and said that he will not resign, despite calls from Massey's family for him to step down.
In May 2023, Campbell interviewed and hired Sean Grayson, who is now behind bars charged with three counts of first-degree murder, aggravated battery with a firearm and official misconduct in Massey's death. Grayson has pleaded not guilty and is being held without bond.
"The rest of this country and the rest of my agency, we do things right. This is an individual that did not. He was trained, he should have known better and I am horrified for the rest of this country," Campbell told ABC News. "I feel bad that he was in the Sangamon County uniform when this occurred because it hurts all of law enforcement. All we want is to protect people."
When asked about his confidence in the vetting process that went into hiring Grayson, Campbell said that the issue was Grayson, not the process itself.
RELATED: Sonya Massey's mom called 911 day before shooting to report daughter was having a mental breakdown
"The vetting process has worked very well for a long time. This is an individual that acted outside the scope of his authority, the scope of our policies and procedures in the law. You can't predict that," he said.
Grayson was fired from his job as sheriff's deputy after he fatally shot Massey while responding to her Springfield, Illinois, home on July 6 after she called 911 for help.
During a community event on Monday in Springfield, Campbell told community members that on the night of her death, law enforcement failed Massey.
"Sonya Massey - I speak her name and I'll never forget it," Campbell said. "She called for help and we failed. That's all she did, call for help."
ABC News has also obtained audio files from four 911 calls made by Massey and her mother about mental health crises in the days leading up to her death.
In a 911 call made on July 5, the day before Massey was fatally shot, Massey's mother, Donna Massey, told the 911 dispatcher that her daughter was having a mental breakdown.
RELATED: Illinois sheriff says his department 'failed' Sonya Massey, woman shot to death by deputy
"She's not a danger to herself. She's not a danger to me. But when she gets upset, then she thinks everybody's after her, like paranoid schizophrenic," Massey's mother said on the 911 call. "I don't want you guys to hurt her, please."
Massey's mother also asked the 911 dispatcher not to send any "combative" or "prejudiced" police officers to help her daughter.
"The 911 calls capture the heartbreaking pleas of Sonya's mother, who desperately sought help for her daughter while expressing her deep fears about the potential for violence at the hands of the police," civil rights attorney Ben Crump, who is representing Massey's family, said in a statement to ABC News. "Despite these warnings, Sonya, a woman struggling with her mental health, was met with deadly force in her own home."
According to personnel files obtained by ABC News, a third-party complaint was filed in May 2024 against Grayson at Sangamon County alleging that he inappropriately handled an encounter with a 17-year-old girl while Grayson was looking for a suspect in the stabbing of three people.
The complaint alleges that Grayson, 30, asked the minor to let him into a house nearby without knowing her relationship to the house or speaking to an adult. Grayson allegedly accused her of lying and threatened to detain and handcuff her after she did not let him into the house.
According to documents, a review of Grayson's body camera footage determined that his actions "were warranted given the serious nature of the call." ABC News has not seen this footage.
Grayson's employment file stated that no formal investigation was conducted regarding this complaint.
Grayson's job with Sangamon County was one of six different police jobs he held over the past four years.
Prior to his employment with Sangamon, Grayson worked at the Logan County Sheriff's Office for just under a year. According to audio files obtained by ABC News, Grayson's then-boss, Logan County Chief Deputy Nathan Miller, expressed concerns over Grayson violating department policy and submitting inaccurate reports while discussing his mishandling of a traffic case.
"Just me asking you those questions, you got a report writing violation for policy. You got an accuracy violation for policy. You got a standard of conduct violation for policy and we're 48 seconds into this," Miller said.
Miller said he and Grayson have "had this conversation before" and called Grayson's behavior "extremely concerning."
Grayson did not receive any policy violations, as Miller put a hold on the report to discuss the inaccuracies with him before officially submitting the document. Grayson ultimately resigned from that position.
Campbell told ABC News that Sangamon County was not aware of this incident when Grayson was hired. Without knowledge of his disciplinary issues at Logan County, Campbell said that Grayson presented no red flags.
He also called Grayson's employment history at five previous agencies over a short period of time something that has become strongly criticized in the national attention on this case -- a "standard career path" in law enforcement.
"I looked at it as a plus," Campbell said about Grayson's career path. "Plus he had no, he had no problems with those agencies. There was nothing reported to us that would concern us. There was no use of force complaints and things like that. That would be something that we would be very concerned about."
"I know that the general public doesn't understand that; they assume maybe something nefarious happened at one of those agencies. But it didn't. It's simply a rise in his career," he said.
Campbell also told ABC News that he has not yet spoken with Massey's family directly, but he disagrees with their call for him to step down, saying that his resignation would "do no good."
Prior to his four-year career in law enforcement, Grayson served as a 91B (Wheeled Vehicle Mechanic) in the Regular Army for just under two years. Grayson was discharged for "misconduct (serious offense)," according to documents obtained by ABC News.
Grayson was discharged on February 24, 2016, after beginning service on May 5, 2014. He served for a total of one year, nine months and 19 days, Grayson's certificate of discharge from active duty shows.
The U.S. Army, citing the Privacy Act and Department of Defense policy, said it is prevented from releasing information relating to the misconduct of low-level employees or characterization of service at discharge.
Grayson was charged with two DUI offenses in Macoupin County, Illinois, in August 2015 and July 2016, according to court documents. The first incident happened while he was still in the Army.
He pleaded guilty to both charges and paid over $1,320 in fines and had his vehicle impounded as a result of the 2015 incident. In 2016, Grayson paid over $2,400 in fines, according to court records.
The Illinois Fraternal Order of Police Labor has dropped its initial grievance seeking to have Grayson reinstated, the group announced on Tuesday.
ABC News' Tesfaye Negussie contributed to this report.