Investigators have determined a cigarrette was the cause of a fire that killed a woman on Valentine's Day.

The fire started just after 4 a.m. on Feb. 14  in a back bedroom of a twin home at 3308 N. Ruch St. in Whitehall Twp., Lehigh Co., officials said.

Tina Groller died of injuries she suffered when she went back inside the burning home to find her cat, officials said.

Groller, 56, initially made it out of the home safely with her husband and their son, but she went back inside to try to find the cat, officials said. Firefighters later found her with severe burns on the second floor.

Cigarettes were found in the son's bedroom, and it appears one of them caused the mattress in the room to catch fire, said Chief Robert Benner, Whitehall Fire Dept.

The fire was contained to the bedroom, but the rest of the house suffered heat and smoke damage, Benner said.

The fire was ruled an accident.