A 22-year-old Joliet man faces a murder charge after allegedly shooting and killing a Walmart employee at a Hammond store Monday, Nov. 2.

Dorian Kevon Robertson was charged Nov. 3 in the death of Dakota Norwood, 21, of Chicago, according to Region News Source. Hammond police confirmed the charge Wednesday and said Robertson was taken to the Lake County Jail, ABC7 Chicago reported.

The Lake County Coroner's Office identified Norwood on Nov. 3. An autopsy determined she died from multiple gunshot wounds, and her death was ruled a homicide, according to the Chicago Sun-Times.

The shooting happened at the Walmart North Supercenter at 1100 5th Avenue in Hammond. Police were called shortly after 9 a.m., after an off-duty Hammond police officer working store security reported gunfire and said a suspect was in custody, NBC Chicago reported.

Police said an initial investigation found that Robertson and Norwood knew each other and had been in a relationship. The nature and length of that relationship remained under investigation, according to the Sun-Times.

What the probable-cause affidavit describes

According to the affidavit, store surveillance showed Robertson arriving at approximately 8:40 a.m. and entering the store. At about 8:58 a.m., he was seen following Norwood as she stocked shelves in an aisle.

At approximately 9 a.m., Norwood moved a rolling cart down the aisle while Robertson followed. The affidavit says she looked back as he approached in what appeared to be an aggressive manner.

Robertson allegedly pushed the cart from behind her and appeared to grab her when she turned around. The two began fighting and fell to the floor. A handgun appeared to fall from Robertson's possession during the struggle.

The affidavit states Norwood was on top of Robertson at one point, and both struck each other with closed fists. Robertson kicked her away, and another Walmart employee stepped between them.

Robertson then allegedly returned to the handgun, picked it up, pointed it at Norwood and fired multiple rounds. Surveillance video showed him continuing to shoot while she was on the ground, according to the affidavit.

A Walmart employee who witnessed the shooting told investigators she heard a struggle and saw Robertson pick up a handgun. She said she yelled warnings to employees and customers. The witness told investigators she did not hear a verbal argument before the physical altercation and did not know whether the two knew each other.

Another employee who intervened reportedly told investigators that Norwood said Robertson had pushed her and was responsible for the altercation, according to the affidavit.

Robertson's account

Robertson told investigators he and Norwood had been in an on-and-off relationship for several months, the affidavit states. He said he went to the store to shop and speak with her about statements she had made.

Robertson admitted pushing the cart Norwood was using but said she turned around and punched him, according to the affidavit. He claimed he hit his head when he fell and could not remember what happened afterward. When investigators asked about the shooting, he described everything as a blur.

Investigators said his claim that he could not remember what happened after falling was inconsistent with surveillance video.

Police response and investigation

After the gunfire, an off-duty Whiting police officer and an off-duty security officer searched the store, according to the affidavit. The security officer located Robertson, who surrendered and was detained. A handgun consistent with the weapon seen in surveillance footage was recovered nearby.

Hammond police said the shooting appeared to be an isolated incident and that there was no ongoing threat to the public, the Chicago Tribune reported.

Walmart said it was working with authorities and providing on-site mental health resources for employees following the shooting, according to the Tribune's initial coverage.