Authorities have ruled the carbon monoxide deaths of two people found inside their Rye Brook home accidental.

The bodies of Carl Persson, 85, and his stepgrandson Joseph Pendrak, 50, were found by relatives just after 12 p.m. Monday at 9 Maywood Ave. Authorities say the two likely died in their sleep as the undetectable, toxic fumes crept into the house.

In the garage, police say they found a cigar stub inside Persson's car, which was out of gas, had a dead battery and the ignition was still on. They say the interior door connecting the garage and house was closed, which has led investigators to believe the gas may have traveled from a gap in the doorway or a ventilation system.

Police have not yet determined how long the car was running before they arrived.

In 2010, a New York state law went into effect requiring all new and existing homes to be equipped with carbon monoxide detectors. Police tell News 12 that the house on Maywood Avenue didn't have detectors.