PACC said the dog went into cardiac arrest and despite the veterinarian's best efforts, they were unable to save her life.
Earlier this week, PACC employees said Lovely had about a 50 percent chance of surviving her injuries.
Dean Sherfield Finley of Tucson is accused of intentionally setting the dog on fire inside a home.
According to authorities, Finley purchased two gallons of gasoline on May 7 and returned home. A family member noticed the dog was "wet" and when the person went to pick the dog up, Finley lit the dog and a corner of the residence on fire.
The suspect was arrested for arson of an occupied structure, criminal damage and animal cruelty.