Crime scene tape surrounds the Diamond Lane Apartments, 555 Deepwoods Drive in Mundelein, after a shooting that left Herbert Lomax, 48, of Mundelein, (inset right) dead and a woman injured Tuesday morning. Deandre Y. Harris, 21, of South Holland, (inset left) has since been charged in connection with the homicide. | Background Photo: Woo-Sung Shim / Lake and McHenry County Scanner; Insets: Provided

A mother, along with her boyfriend, came home to find her daughter’s boyfriend brandishing a gun in their Mundelein apartment and prosecutors say he soon after opened fire on them, killing the man and seriously injuring the woman.

Deandre Y. Harris, 21, of South Holland, was charged with two counts of first-degree murder, a Class M felony, and one count of aggravated battery by discharge of a firearm, a Class X felony.

Lake County Assistant State’s Attorney Jeffrey Facklam said Harris was at his 19-year-old girlfriend’s residence at the Diamond Lane Apartments, 555 Deepwoods Drive in Mundelein, on Tuesday morning.

Harris’ girlfriend’s mother and the mother’s boyfriend, who both also live at the apartment, had left the residence but returned later in the morning.

Police officers and detectives from several agencies respond to a shooting that left a man dead and a woman injured at the Diamond Lane Apartments, 555 Deepwoods Drive, in Mundelein Tuesday morning. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

Lake County Coroner Jennifer Banek identified the mother’s boyfriend as Herbert Lomax, 48, of Mundelein.

They entered the apartment to find Harris holding two guns and pointing them, Facklam said.

The woman’s daughter was standing near Harris trying to calm him down.

The mother heard one or two gunshots and fell to the floor. She saw Lomax on the floor near the kitchen, Facklam said.

Investigators with the Lake County Major Crime Task Force respond after a shooting that left Herbert Lomax, 48, of Mundelein, (pictured left) dead and his girlfriend injured at the Diamond Lane Apartments, 555 Deepwoods Drive in Mundelein, Tuesday morning. | Photo – Left: via Facebook; Photo – Right: Woo-Sung Shim / Lake and McHenry County Scanner

Harris moved towards the front door and she then heard two or three more gunshots, Facklam said. One of the shots struck her in the leg.

The Mundelein Police Department, Mundelein Fire Department and Countryside Fire Protection District responded to the scene around 11:40 a.m. after receiving 911 calls for the shooting.

Lake County Major Crime Task Force Spokesman Christopher Covelli said 911 callers reported two people had been shot and one of them was unresponsive.

Harris and the daughter fled the apartment in her car. Officers broadcast the information to law enforcement agencies throughout the region over the Illinois State Police Emergency Radio Network (ISPERN) and other police systems.

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Officers arrived and found Lomax suffering from multiple gunshot wounds. They also found his 47-year-old girlfriend seriously injured, Covelli said.

Police officers deploy a drone after a shooting that left a man dead and a woman injured at the Diamond Lane Apartments, 555 Deepwoods Drive, in Mundelein Tuesday morning. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

Lomax was transported by ambulance to an area hospital with a gunshot wound and was pronounced dead after arriving, Covelli said.

The adult female victim was also transported by ambulance to an area hospital and is expected to survive.

The vehicle, reported to be a Chevrolet Blazer, was spotted in Chicago around 12:40 p.m. Tuesday, according to police radio traffic.

Law enforcement, including a police helicopter, responded to the area of Interstate 94 on the south side of Chicago as the vehicle was on the move.

Illinois State Police and other agencies conducted a traffic stop on the vehicle in the area of southbound Interstate 94 at 130th Street, police radio traffic indicated.

Police officers and detectives from several agencies respond to a shooting that left a man dead and a woman injured at the Diamond Lane Apartments, 555 Deepwoods Drive, in Mundelein Tuesday morning. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

They ordered both occupants of the car out at gunpoint and took Harris and an adult female into custody. The female had been reportedly driving and Harris was a passenger.

Harris told police there were guns in the car and officers searched the vehicle pursuant to a search warrant and recovered one firearm and one BB gun, Facklam said.

The female victim’s daughter told police that there had been ongoing issues between her and her mother’s boyfriend.

Investigators with the Lake County Major Crime Task Force respond after a shooting that left a man dead and a woman injured at the Diamond Lane Apartments, 555 Deepwoods Drive, in Mundelein Tuesday morning. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

She asked Harris the day before to stay at her house overnight, which he did.

They woke up and her mother and Lomax were gone but came back later that morning, Facklam said.

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Facklam said Harris confronted her mother’s boyfriend about an issue between her and Lomax, at which time the two began arguing and Harris pulled out a gun.

Harris’ girlfriend told police that she knows Harris usually carries a gun.

Police officers and detectives from several agencies respond to a shooting that left a man dead and a woman injured at the Diamond Lane Apartments, 555 Deepwoods Drive, in Mundelein Tuesday morning. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

The daughter began panicking and heard several more shots, Facklam said. She fled the apartment with Harris to drive him back to his house in South Holland and told investigators she did not know what else to do.

Harris was also interviewed and told investigators he confronted Lomax over an issue with his girlfriend, Facklam said.

He said Lomax walked aggressively towards him so he pulled out his gun and shot him and then shot him again after he did not immediately fall, Facklam said.

A police officer sets up crime scene tape at the Deep Wood Plaza after a shooting that left a man dead and a woman injured at the nearby Diamond Lane Apartments, 555 Deepwoods Drive, in Mundelein Tuesday morning. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

Harris told investigators he then moved towards the front door of the apartment and shot the victim again because he thought Lomax was turning towards him. Five shell casings were recovered.

Harris reported that Lomax was unarmed and did not physically batter him, Facklam said. He also told investigators he did not know how his girlfriend’s mother was shot in the ordeal.

“The defendant initiated an argument with the victim and then pulled out a gun and shot an unarmed person. Despite defendant’s claims of self-defense, it was the defendant who was the aggressor. He started the argument and he is the only one who used or even had a weapon,” Facklam said.

Investigators with the Lake County Major Crime Task Force respond after a shooting that left a man dead and a woman injured at the Diamond Lane Apartments, 555 Deepwoods Drive, in Mundelein Tuesday morning. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

“In fact, the defendant also apparently had a BB gun, a less lethal option, or could have easily just left the apartment. Instead, the defendant fired five shots inside the apartment with two other people present. The defendant showed no regard for their safety – evidenced by one of them being shot in the leg,” Facklam said.

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The Lake County State’s Attorney’s Office filed a petition to detain Harris pending trial, arguing he poses a danger to the community.

“The evidence also shows that this shooting was deliberate. The defendant did not fire multiple shots in short succession. All witnesses describe the defendant firing initial shots and then moving towards the front door. Rather than leaving, the defendant fired more shots with the victim on the ground. This case is one of violence with multiple victims,” Facklam said.

Lake County Judge Michael Nerheim granted the petition during a detention hearing held on Thursday afternoon.

Police officers and detectives from several agencies respond to a shooting that left a man dead and a woman injured at the Diamond Lane Apartments, 555 Deepwoods Drive, in Mundelein Tuesday morning. | Photo: Woo-Sung Shim / Lake and McHenry County Scanner

An attorney for Harris argued for his release and said that the victim in the case had been “predatory” towards Harris’ girlfriend and is bigger in size than Harris, who was protecting his girlfriend by confronting Lomax. The attorney also said that Harris did not intentionally shoot his girlfriend’s mother.

The shooting prompted a massive police response from a slew of departments throughout Lake County.

Officers with rifles were seen setting up a perimeter east of Route 45. Drones were also deployed.

The Lake County Major Crime Task Force, which consists of investigators from agencies in the county, was requested to the scene.

Investigators were seen taking photos of the apartment, conducting interviews and entering nearby businesses in the Deep Wood Plaza shopping center to learn more about what happened.