"She really lived what she believed," said Gail Aycock, a friend of more than 20 years.
Mullins told her sister that she'd be back Sunday. But New Mexico State Police Lt. Robert McDonald confirmed Monday that Mullins, 54, died in an accident on Interstate 25 at about 6:45 p.m. Sunday. She lost control of her car just north of the La Cienega exit, slid off the road and struck a barrier wall. Her car then rolled back onto the highway, settling in the middle of the two northbound lanes.
McDonald said while Mullins' car was disabled, a 2003 Chevy truck struck it. McDonald said the truck's driver was unable to stop in time after realizing what was ahead of him. Mullins died at the scene. Alcohol was not a factor in the crash.
"Just terrible conditions out there," McDonald said.
Shelli Petty of Los Alamos said her sister was a teacher in Santa Fe Public Schools for 23 years.
"She was the youngest sister. Right now, it's just hard to believe," Petty said.
The accident was one of many crashes Sunday evening as snow from a winter storm built up on the highway.
On Monday, Santa Fe Public Schools grief counselors addressed students at Kearny Elementary School, where Mullins had taught third grade for 16 years. Counseling will be available to students all week, and the school and student council are planning a memorial service for Mullins early next week, Principal Jennifer Baca said.
Baca said Mullins was known for her compassion and that many of her students excelled in reading. "She poured her heart out into her work," Baca said.
Mullins sister, Petty, the owner of Children's Montessori Preschool in Los Alamos, and Betty Anne Pacheco, a teacher at Atrisco Heritage High School in Albuquerque, boasted about their sister in phone conversations Monday.
Mullins earned a degree in education from New Mexico State University and then taught in schools in Deming, Carlsbad, Albuquerque and Santa Fe. She was the first of the sisters to begin teaching, and then both Petty and Pacheco followed suit.
"She was amazingly able to do things fairly," Pacheco said.
Mullins also was an active member of her church, where she taught Sunday school classes and even choreographed a play. Mullins never married or had children of her own, but her sisters say her students were her children. "She treated them like her own," Pacheco said.
In her spare time, Mullins operated a Jazzercise studio in Santa Fe. "Exercising and teaching was her whole life," Pacheco said.
Petty and Pacheco are planning a memorial service for Mullins at the City of Faith Christian Fellowship. A date has not been set.
"It's going to hit our entire community," Baca said of her soft-spoken, yet passionate colleague. "She was a hero in our community of educators."
Contact Nico Roesler at 986-3089 or email@example.com. Follow him on Twitter @nicoroesler.