A Madison County jury took about six hours on Thursday to convict 31-year-old Samuel J. Chatman on all counts in the April shooting of a man who was hit four times as he approached a car outside his mother's home on Locust Street in Alton. The victim, identified by prosecutors as Semaj J. Johnson-Joiner, was shot in the face, chest, shoulder, and hip on April 22, 2026, and survived after receiving emergency treatment at a hospital in St. Louis.
Chatman was found guilty of attempted murder, aggravated battery with a firearm, aggravated discharge of a firearm, and possession of a firearm by a repeat felon, according to First Alert 4. As reported by RiverBender.com, the verdict came just four months after the shooting occurred, a timeline Madison County prosecutors described as an unusually rapid path to conviction for a case built on this much digital evidence.
Video, Cell Records and License Plate Data Built the Case
Investigators from the Alton Police Department pieced together the case against Chatman using a combination of surveillance footage gathered from local businesses and residents, cell phone records, and license plate reader data to trace his movements before and after the shooting, per the same RiverBender.com account. During closing arguments, Assistant State's Attorney Luke Yager told the jury that detectives had reviewed “video after video” to place Chatman at the scene, the outlet reported.
That technological capability traces back to a $100,000 Department of Justice Smart Policing grant the Alton Police Department secured in collaboration with Southern Illinois University Edwardsville criminal justice professor Dennis Mares, according to Southern Illinois University System board records from August 2024. The funding expanded the department's surveillance camera network and license plate reader infrastructure as part of an ongoing SIUE partnership aimed at improving public safety and data transparency in Alton.
Suspects Fled to Missouri Before Multi-Agency Arrest
Chatman and co-defendant Anthony L. Shanklin fled across state lines to the St. Louis area immediately after the shooting, leading to their arrest on April 28, 2026, during an early morning operation involving Alton Police, Illinois State Police, St. Louis city and county police, and the U.S. Marshals Service, as detailed by RiverBender.com. Alton Police Chief Jarrett Ford credited cross-border agency cooperation for the quick capture of both men. Madison County Judge Hackett then ordered Chatman and Shanklin held in custody without bond pending extradition back to Illinois, the outlet reported.
Shanklin, 34, is believed to have been the driver of the car Chatman was riding in during the shooting, per First Alert 4's reporting. He is charged with attempted murder and is still awaiting trial, according to RiverBender.com, leaving his case as the remaining open question in the Locust Street shooting.
Prosecutors Point to Severity of Class X Charges
Madison County State's Attorney Tom Haine said in a statement that violent crime in the community “will be thoroughly investigated and aggressively prosecuted,” praising prosecutors Luke Yager and Zac Cato for bringing the case to trial in four months, according to RiverBender.com. Haine noted that mastering a massive volume of video and digital evidence in that span was an extraordinary effort by the prosecution team.
Chatman faces up to 85 years in prison when he is sentenced later, First Alert 4 reported. Under Illinois law, Class X felonies are the most serious offenses short of first-degree murder, carrying mandatory prison terms of 6 to 30 years with no possibility of probation, according to the Law Office of Stephen L. Richards. Illinois's Truth-in-Sentencing statutes, per the Illinois General Assembly, also require anyone convicted of attempted first-degree murder or aggravated battery with a firearm to serve at least 85 percent of their total sentence before becoming eligible for parole or early-release credit.
The conviction adds to a string of recent Madison County prosecutions targeting gun violence in Alton. In July, prosecutors secured a 50-year sentence over a 2024 slaying tied to the drive-by shooting death of a 13-year-old girl in Alton, part of what the state's attorney's office has framed as a sustained crackdown on violent firearm offenses in the city.
