The incident took place in Danbury around 3 p.m., Monday, Nov. 28 on Clayton Road.
The caller stated that family members had not seen or heard from two of the residents since Sunday, Nov. 27, said the Danbury Police.
Upon arrival, officers discovered two adults, one man and a woman unconscious on the floor of a basement bedroom, both with gunshot wounds to the head, police said.
Police said fire and EMS personnel responded but both victims were dead.
The names of the victims are being withheld pending notification of next of kin.
"At this time, we believe this is an isolated incident but it is an active investigation," said Danbury Police Chief Patrick Ridenhour.
Anyone with information is asked to contact Danbury Police at 203-790-TIPS.
This is a developing story. Check back to Daily Voice for updates.
Click here to follow Daily Voice Windham-Willimantic and receive free news updates.