SCOTTSDALE, AZ (3TV/CBS5) -- Scottsdale police are investigating after a woman told police she killed her mother.
According to Scottsdale police, the murder happened Sunday in a neighborhood near 64th Street and Osborn Road. But police first found out about the incident on Monday afternoon.
WATCH VIDEO: Police say Scottsdale woman killed her mother
[WATCH BREAKING: Woman accused of suffocating and killing her mom]
Scottsdale police say the suspect, 46-year-old Holly Brennan, went to a neighbor and asked her to call police.
According to court documents, the neighbor gave the phone to the suspect and told the dispatcher that "her name was Holly and she needed police there."
Brennan also admitted to killing her own mother.
"I killed my mom," you could hear Brennan saying in a 911 call. "I smothered her."
During the call, the 911 dispatcher asks:" Is your mother not breathing?" Brennan replies: "Oh, my mother is dead."
The dispatcher asks: "And how did you kill your mom?" And Brennan replies: "I smothered her."
Brennan later gave her address and clarified that she was there by herself and that her mother was in the bedroom. Officers later arrived to the apartment complex.
When officers asked how Brennan killed her mother, she told them that she "smothered her," and then said "my mother is dead."
Scottsdale officers then conducted a welfare check inside the apartment and found 79-year-old Sharon Simmons lying on her back, partly on a bed. She was pronounced dead by officers. Police say Simmons also had a pillow partially covering her face.
During police questioning, Brennan told officers that she "hated" her mother and "wanted her gone."
Court paperwork indicated Brennan killed her mom on Mother's Day morning.
She told officers that she approached Simmons and pushed her down on the bed. Brennan then proceeded to smother her with a pillow in her hand, police said. Brennan told officers that the incident lasted for a couple of minutes.
Brennan added that she had thought of killing her mother on two different different occasions, once in 2017 and another in December 2018. After the second incident, she sought treatment.
Police say after she killed her mother, Brennan said that she walked to a nearby Circle K and purchased "some vodka for herself and a gin for her mother."
When she returned home, Brennan placed a bottle of gin on Simmons' stomach.
"They handcuffed her and sat her down on the ground, and then they wouldn't let me out that door because they taped it all off," said Mike Bennett, who also lives in the apartment complex. "She said, 'I did it, I smothered her with a pillow,' and I'm like, ‘Am I hearing this?’"
Bennett said he came face-to-face with Brennan earlier in the day on his way back from the laundry room.
"I said, ‘Hey, how you doing?’ And she gives me this blank stare, like [I’ve] got three heads or something,” Bennett said.
Another neighbor, Patti Christian, said she had previously seen officers visit the home.
"Two times at least," Christian said. "They would go in and come out and say, ‘Oh, it was just something light."
Police said there is a history of domestic violence surrounding this family.
Brennan was later booked into the Fourth Avenue Jail and is currently facing a second-degree murder charge.
[SLIDESHOW: Mother killed by daughter at Scottsdale apartment]