A lady has been accused of homicide after a pet duck assisted US with policing to break the instance of her missing grandma in North Carolina, authorities said.

Nellie Sullivan, who would be aged 93 if she were still alive, disappeared sometime in 2020.

Investigators have been searching for Ms Sullivan ever since without a trace.

But a breakthrough in the case came earlier this month, on 14 April, when a pet duck ran under a trailer in Candler, North Carolina, which led its owners to discover a container holding the grandmother’s body.

Ms Sullivan’s granddaughter, Angela Wamsley, 46, and grandson-in-law, Mark Alan Barnes, 50, have been charged with first-degree murder over her death.

Police say they do not have a definitive date when Ms Sullivan was killed, but believe she has been dead for some time.

The suspects had been under investigation in connection to her death since December 2020, Buncombe County Sheriff’s Office spokesperson Aaron Sarver said.

They were initially arrested on charges spanning animal cruelty and drug possession.

But by December 2021, Wamsley and Barnes had both been charged with concealing a death, the sheriff’s office said.