AURORA, Colo. -- A 21-year-old woman who allegedly left her dogs locked in a basement to die when she moved out of her rental house is now facing more serious charges.

On Friday, Arapahoe County prosecutors announced that Natasha Rice will face two felony charges of aggravated cruelty to animals, not a misdemeanor charge.

Arapahoe County Sheriff's deputies discovered the dead dogs while serving an eviction notice on March 13. The dogs had not been left with any food or water and a chair had been propped against the basement door to keep it closed, police said.

Rice's neighnors say she had not lived in the home at 3749 S. Nepal Court for two to three weeks. Rice could be sentenced to 18 months in prison and ordered to pay $100,000 if she is convicted on the felony charges.

The animal rights groups People for the Ethical Treatment of Animals and The Humane Society of the United States had been sending letters to Arapahoe County District Attorney Carol Chambers urging more serious penalties, including counseling, jail and a ban on owning animals. If Rice was found guilty of the misdemeanor animal cruelty charge, her maximum sentence would have been 18 months in jail and a $5,000 fine.

Rice told police she called the Humane Society to pick up the dogs when she moved out Feb. 12 but the executive director for the Humane Society said Rice never contacted them. Mary Warren said the Humane Society does not arrange to pick up animals, especially from a locked vacant home.

Leslie De Hoyos, an Arapahoe County animal control officer who was called to Rice's former home, told the Rocky Mountain News that the dogs had tried desperately to escape.

"The door was pretty scratched up and chewed through," she told the paper. "They were trying to get out, but there was a chair shoved under the the handle of the basement door at the top of the stairs."

The basement floor was covered with feces and what appeared to be vomit with bits of insulation in it.

"Every wall that had insulation was chewed up," she said. "They were trying to survive."

De Hoyos said she found Cujo, a 1 1/2-year-old male Chihuahua, at the bottom of the basement stairs, and Titan, a 1 1/2-year-old male shepherd mix, about 10 feet from Cujo.

"They were just skin and bones," she said. "The muscle mass was gone. The body fat was gone."

She estimated that Cujo weighed only 2 pounds and Titan about 30 pounds when found -- both about half of what they should have weighed.

"This is the first time I walked into something like this. It was pretty gut-wrenching emotionally. It's hard to understand how humans can do that to helpless animals," she told the paper.

It was not the first time that animal control had contact with Rice about the dogs. On Nov. 26, animal control officer Anthony Youngblood was called because Rice's dogs were reportedly running loose.

Youngblood said he tried to speak with Rice, but she refused to answer the door. She came out only when he attempted to load the dogs into his truck, he said. Youngblood said he didn't issue a citation since it was her first offense.