UPDATE Monday, Oct. 2, 2017 at 3:35 p.m.

The Knox County Sheriff's Office has said a missing woman and her grandson have been found safe.

The two went missing Sunday night.

The Knox County Sheriff’s Office Major Crimes Unit has thanked the public for their assistance in the matter.

ORIGINAL STORY Monday, Oct. 2 at 3 p.m.

The Knox County Sheriff’s Office has asked for help finding a missing woman and her infant grandson.

Melissa Irwin, 51, was last in contact with her family on Sunday night. Investigators said she left her home with her 4-month-old grandson, Adam Johnson, Jr., and said she was going to the store.

According to the Knox County Sheriff's Office, Irwin was contacted by her family around 8 p.m. and said she just left Walmart on Clinton Highway and was on her way home.

Irwin is described as a 5-foot tall, white female, about 80 pounds, with brown hair and brown eyes.

Deputies said she was last seen wearing a white and grey striped shirt, blue jean leggings, tennis shoes, and wire frame glasses.

Irwin left in a black 2012 four-door Ford Focus bearing Tennessee license plate 2C86W4 and has a diminished mental capacity, according to the Knox County Sheriff's Office.

Johnson is described as a white male, 14 pounds, with blonde hair and blue eyes. Irwin has custody of Johnson.

Anyone with information is asked to contact the Knox County Sheriff’s Office Major Crimes Unit at (865) 215-2243.