The younger sister of a woman who authorities say was killed by their mother has pleaded not guilty to charges that she helped dump the body in a field in Ohio.

Nineteen-year-old Hannah Tyburski entered the plea Thursday in Lorain County. The Oberlin College student is charged with tampering with evidence, obstructing justice and abuse of a corpse.

Authorities say she helped her mother remove the body of 26-year-old Rachele Tyburski from a suburban Cleveland home March 15, two days after Rachele Tyburski was suffocated. Forty-six-year-old Janet Tyburski has pleaded not guilty to aggravated murder.

Authorities haven't said why they believe Janet Tyburski killed her daughter.

A relative told The Associated Press that Rachele Tyburski had mental health issues and her mother was the primary caregiver for Rachele's 4-year-old son.