Toledo police Sgt. Joe Heffernan said the deaths of the five extended family members did not appear to be accidental, The (Toledo) Blade reported.
Lucas County Coroner James Patrick said the victims were a 56-year woman, her granddaughters, ages 10 and 5, a 7-year-old grandson, and a 32-year-old man identified as the uncle of one of the children. Their names had not been released.
City police were called to the home at 3:17 p.m. on a check safety request and the bodies were found when crews arrived at 3:36 p.m., the newspaper said. Heffernan would not say what led authorities to determine carbon monoxide caused the deaths.
Police were investigating the home's garage, The Blade said.