PHILADELPHIA (CBS) — A couple didn’t show up to work Wednesday and it led to the discovery of four family members murdered inside their West Philadelphia home. Acting Philadelphia Police Commissioner Christine Coulter confirms 29-year-old Maurice Louis confessed to the murder of his mother, stepfather and two brothers.

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Louis’ mother, 51-year-old Janet Woodson, was killed in the shooting, along with her husband, Leslie Holmes. Police also say Louis killed his two stepbrothers — 18-year-old Sy-eed Woodson and 7-year-old Leslie Woodson Jr.

Police say the 29-year-old suspect was found in a second-floor bedroom and was taken into custody. Sources say the suspect suffers from a mental illness.

Coulter says something happened within the family that set him off, prompting him to purchase the shotgun on Tuesday that was recovered at the scene. Police continue to work towards a motive.

“He just obviously had some kind of hatred for family members or in that moment did and made a decision to kill them,” Coulter said.

Seasoned investigators told CBS3 the scene was something out of a horror flick.

It’s believed the shooter was lying in wait for each victim and used a birdshot in the shotgun. Police say the shots would have had to be at point-blank range for them to be lethal.

Police say Woodson was shot dead by the front door. Her husband was killed by the basement door. Sy-eed was shot to death in his bedroom and his 7-year-old brother was shot and killed in the kitchen. Sources say the victims were shot in the head.

“It’s tough and it’s taken a toll on our officers. It’s never easy to go to a crime scene and it’s that much harder with a child involved,” Philadelphia Deputy Police Commissioner Joseph Sullivan said.

As you can imagine, the victims’ family is devastated.

Police say the parents were at work Tuesday, but when they didn’t show up for work Wednesday, co-workers called police. Police showed up to the house around 2 p.m. and discovered the gruesome scene.

When police arrived at the house around 2 p.m., Coulter says Louis pointed them towards where they could find the bodies.

Minutes after the bodies of four loved ones were removed from the home, family and friends gathered to pray over the immense tragedy.

“I’m so numb. I can’t even express what I feel now,” Janet Woodson’s older brother, Reggie Woodson, said. “I don’t know what I’m going to do.”

By phone from Atlanta, Janet Woodson’s younger sister, Kia Morgan Smith, recalled the moment her mother called to tell her about Janet’s death.

“Just screaming. And I said, ‘Please tell me it’s not true. It’s not true, It’s not true,’ and she said it’s true,” Smith said.

Smith remembered the two boys killed in the shooting.

“Sy-eed is such a smart kid. He’s got awards, he’s got good grades,” Smith said. “[Leslie Jr.] was so talkative and he was so smart. It just breaks my heart.”

Smith believes Louis may have suffered from mental health issues.

“[Janet] did say something was going on with him,” Smith said. “Why would you act out in such a horrific way? You know, mental illness is real.”

With her sister now gone, the little comfort Smith has is from the many positive memories with Woodson she’ll forever cherish.

“Just hearing her sweet voice and her sweet spirit going around her. You just felt safe and you felt loved. She just oozed and exuded love,” Smith recalled.

She says her sister’s passion was hairdressing. She was even saving money to open her own salon.

As for Louis, police sources say he is cooperating with detectives and has confessed to the killings.

CBS3’s Joe Holden and Greg Argos contributed to this report.