DENVER (CBS4) – Firefighters pulled a man from a burning house early Tuesday morning.

Authorities said a neighbor reported smelling smoke at about 1:45 a.m. Responding fire crews didn’t immediately spot a fire, but while they were driving through an alley firefighters noticed there was smoke seeping from the top of a door.

They found the man, identified as Thomas Hardy, unconscious inside the house, which is located at Downing and 3rd.

Hardy needed CPR on the scene and was taken to the hospital. He remains in critical condition at Denver Health Medical Center.

“Thomas sustained injuries related to smoke inhalation,” Cindy Matthews with Denver Health said in a statement. “Thomas’ friends wish to thank the community for their many thoughts and prayers during this difficult time.”

Two dogs were also found dead inside the house.

The fire remains under investigation and the cause is undetermined so far. Investigators believe it started in the kitchen and traveled to the bedrooms.