When police arrived, screams for help were coming from a 61-year-old woman identified as Kaur Balbir, a petite mother of two who was at the mercy of her 32-year-old son, identified as Satnam Singh, as he beat her with a frying pan.
Police ended up firing five times at Singh, killing him.
Neighbors throughout The Dorado heard the commotion and figured it was coming from apartment 2D.
"I heard screaming and yelling, heard the lady crying really hard and then she was saying stop, stop, help, I heard some metal and then didn't hear her screaming anymore," said one neighbor.
Police say that's because by then Balbir had a fractured skull, left arm in several places and her shin.
Moments before, police had received an urgent call from the victim's other son,
He was worried about his mother and wanted them to check on her.
When the four officers arrived, they tried to enter the apartment but couldn't.
They got keys from the super but the doors was chained shut from the inside, although through a small opening they could see the suspect standing over his mother striking her with the pan.
Police say they forced their way in, identified themselves and ordered Singh to drop the skillet, he refused and then police maintained he raised the pan again, as if he was going to hit his mother, they opened fire killing him.
Neighbors weren't surprised to hear what happened, saying they were terrified of the suspect, who used to pace back and forth in the lobby.
Jessica Castro told her kids to steer clear of him. "He just didn't look right at all, he was to himself, wouldn't look anyone in the eye, something was wring with him," she said.
Balbir remains at Lincoln Hospital in critical condition.
Police say Satnam Singh had no official psychological history on record.