By Jennifer Pierce, NEWS 9

OKLAHOMA CITY -- Authorities are investigating the death of 3-year-old Larandon Nichols. The boy's adoptive mother and her boyfriend were initially arrested on a complaint of murder, but were later charged with child abuse, neglect and enabling abuse charges.

Larandon died Sunday in his northwest Oklahoma City home.

Next door neighbor Chung Nguyen said he was shocked at the allegations.

"They've always been nice and quiet there's never been a lot of loud noises," Nguyen said.

The arrest affidavit said Alibra Nichols, the boy's adoptive mother, called 911 and reported Larandon was not breathing. When police arrived to the home, the child was not alive.

Investigators noted numerous injuries, in various stages of healing on Larandon's body. Nichols admitted to police she spanked Larandon with a flip flop and said she struck him "too hard". She also told police, her boyfriend Donald Miller "whoops" Larandon with a switch.

Authorities also interviewed the couple's 6-year-old biological son. He said that Larandon was "whooped" with a belt, hangers, sticks and a baseball bat.

Larandon also appeared to be malnourished and small for his age. He weighed only 18 pounds. The normal weight of a child that age is about 33 pounds. The 6-year-old told investigators Larandon would eat different food than the rest of the family.

The couple's biological 6-year-old son and 3-month-old child are in protective custody.

Nguyen said she feels guilty all of this happened next door, and she didn't even know.

"I wish I was there. I wish I could have heard something to call someone to help, or I could have helped out," Nguyen said.