An elderly couple has died in Croton-on-Hudson of apparent carbon monoxide poisoning.

State police say 86-year-old Cornelius Dennis and 85-year-old Joan Dennis died after were found dead earlier this week on Skytop Drive.

Police believe the couple was killed by a buildup of carbon monoxide. It appears when the couple returned home one day, they left their car running in the garage. It's possible they didn't hear the car running, allowing the carbon monoxide to accumulate in other areas of the home.

The couple was discovered on Saturday when a neighbor noticed three days' worth of newspapers outside the couple's home.