PINE RIDGE, S.D. -

The grandmother of a two-year-old boy allegedly killed over potty-training issues, pleads not guilty to hindering the investigation.

Forty-seven-year-old Sonya Dubray was arrested Monday and is accused of altering or destroying evidence and giving false and misleading information to investigators.

Authorities say Kylen Shangreaux was killed by his mother on the Pine Ridge Reservation, in South Dakota in July.

She has pleaded not guilty to murder and child abuse.

The boy's one-year-old half-brother was killed by their father in 2015.