A woman who survived the 2012 massacre at a Colorado movie theater but lost two fingers in the rampage died unexpectedly Sunday, leaving her family looking for answers.

Heather Snyder, 31, was among a group of Red Robin workers who went to see "The Dark Knight Rises" at the Aurora movie theater on July 20, 2012 when James Holmes burst into the facility, killing 12 and injuring 70.

Her father, Rick Snyder, told The Denver Post his daughter's death "was totally unexpected." An initial autopsy did not determine a cause of death and family members may have to wait several weeks to find out, FOX 31 Denver reported.

Her father said she could not forget the fatal shooting and was reminded of it every day because it left her with an amputated index and middle finger.

Heather Snyder died unexpectedly Sunday.

“She never totally recovered from it," he told the newspaper.

After surviving the massacre, Heather Snyder went on to have a daughter and later testified in court against Holmes on May 14, 2015.

In her court appearance, she said her injuries severely impacted her life.

“I was thinking, ‘Oh, my god! What is going on?’ ” she testified about the moment gunfire rang out. In Aug. 2015, Holmes was sentenced to 12 consecutive life sentences plus 3,318 years for the massacre.

A family friend told FOX 31 she was a loving, caring, and courageous woman.

"When you have a wonderful human being that is a support system for everyone that can light up your day, and they’re taken from you, it’s not easy. It’s very difficult," Larry Martinez said.

Family members have created a GoFundMe page asking for help with a memorial service for Snyder and donations to care for her 2-year-old daughter, Kennedy.