CHICAGO (CBS) — The grieving family of an 81-year-old woman found dead in her home in Rosemoor earlier this week wants answers about her gruesome murder, and is offering a $5,000 reward for information leading to an arrest.

Thana Muhammad was the sister of former Ald. Michael Chandler. Another brother is a Chicago police lieutenant. But those powerful connections didn’t prevent someone from killing her sometime last week.

Muhammad, who also was known as Mattie Chandler, was found dead inside her neatly kept home at 100th and Forest on Sunday.

Police have said she was decapitated, but her family said that is incorrect. They said her body was dismembered and placed in two storage bins.

“She did not deserve this, Chicago. This is a monster. This is a monster,” said her granddaughter Camille Durham.

Muhammad’s car was stolen. The silver 2012 Honda Accord was discovered Thursday on the West Side, near Polk and Division.

Muhammad’s family believes someone knows something about who killed the longtime member of the Nation of Islam. They’re offering a $5,000 reward for information leading to an arrest.

“My mother had a right to be safe, and if you know of this person, it is your obligation – your moral obligation – to stand up,” said her daughter, Ashanti Chimurenga.

Through tears, Chimurenga vowed to get justice for her mother.

“I’m coming to the West Side, walking the streets, and I’m asking who saw you?” she said.

Durham said she’s confident her grandmother’s god saw and heard her prayers during her time of need.

“I know she hollered out for her life. I know he reached his hand out for her, and I’m okay with that,” she said.

Chicago Police Supt. Eddie Johnson has said it’s likely the killer knew Muhammad.

“The crime scene was very clean, and there was a lot of deliberation put into this horrific act,” he said. “It’s very likely that the person knew the victim. They put a lot of thought into what they did. Like I said, the crime scene was very clean, so they took their time and meticulously tried to hide what they had done, hide any potential evidence, so it’s hard to say whether it was domestic or not, but I would just – in my time in the detective division, I would speculate that the person did know the victim.”

The superintendent urged anyone with information about the case to contact Area South detectives at 312-747-8271, or submit an anonymous tip at CPDTIP.com