PHOENIX (CNN) -- Ruby, a 9,000-pound elephant who became famous for her abstract paintings at the Phoenix Zoo, was put to sleep Friday after contracting a deadly uterine infection.

During a Caesarean section to remove a fetus that had died, veterinarians discovered that the 320-pound fetus had punctured Ruby's uterine wall and had slipped into her abdomen. The resulting infection and severe peritonitis were determined untreatable.

Veterinarians realized last week that her fetus had died. Attempts to induce labor were unsuccessful.

The plight of 25-year-old Ruby sparked an outpouring of public concern. Visitors sent get-well cards and bouquets and donated mattresses and tires to create a bed for her surgery. Hospitals sent medical supplies, from antibiotics to sterilization equipment.

Ruby became a media star a decade ago when her keepers noticed she liked to hold a stick in her trunk and doodle in the sand. They substituted a paintbrush for the stick, and Ruby's creations raised about $500,000 for the zoo.

"Ruby captured people's imaginations," said Jeff Williamson, executive director of the Phoenix Zoo. "Our obligation was to take advantage ... and try to inspire people to care for creatures in the wild."

Ruby became pregnant in 1996 while visiting the Tulsa Zoo, where she mated with a bull elephant named Sneezy. The normal gestation period for an elephant is 22 months.

Ruby will be buried on the zoo's grounds.