Watch CNN's LIVE TV coverage of the Connecticut elementary school shooting as the story continues to unfold.
(CNN) -- At home and at work, there was no doubting Mary Sherlach's success.
Professionally, she'd worked in three Connecticut school systems before settling in as school psychologist at Sandy Hook Elementary in Newtown, writing on her website that "I truly enjoy working with the SHS staff, parents and children."
Personally, she'd been married to her husband for more than three decades and, together, they were "proud parents" of two daughters in their late 20s.
Details were still emerging Friday night about exactly what happened. But a parent told CNN that she was in a room with Sherlach, the school's principal, Dawn Hochsprung, and its vice principal when they heard a "pop, pop, pop" sound around 9:30 a.m.
The three school administrators headed into the hall to find out what was happening.
Hochsprung and Sherlach didn't come back alive.
Sherlach, 56, was an expert in psychology, having earned her undergraduate degree in that subject at SUNY Cortland and a master's degree at Southern Connecticut State University.
Before becoming a school psychologist, she worked as a rehabilitation assistant at a psychiatric facility, at a group home for disabled adults and as a community mental health placement specialist.
Her experience in education included stints in the Redding, North Haven and New Haven public school systems before landing at Sandy Hook Elementary in 1994. During her time in Newtown, Sherlach kept busy as a member of numerous groups such as the district conflict resolution committee, safe school climate committee, crisis intervention team and student instructional team.
"I ... am always ready to assist in problem-solving, intervention and prevention," she wrote.
In the "About Me" section of her website, Sherlach also spoke extensively about her family.
"My husband Bill and I have been married 31 years and are the proud parents of two beautiful daughters, ages 25 and 28," she said.
Sherlach then went into detail about each of her children, one a high school chorus teacher in southern New Jersey and the other a Ph.D. candidate in chemistry at Georgetown University.
Sherlach listed her interests as gardening, reading and going to the theater. She and her husband lived in Trumbull, Connecticut, and "enjoy traveling and spending time at our lake home" in upstate New York's Finger Lakes region.
Her sudden death prompted Jeanne Stocker to write an emotional tribute on Facebook, saying she was "beyond numb as I lost a good childhood friend."
"She gave her life protecting these children," Stocker said. "Her husband Bill and two daughters are beyond devastation. Just so unfair and horrific too."
People are sharing their concern and sadness over the Newtown school shooting. What are your thoughts? Share them with CNN iReport.
CNN's Diana LaPosta, Ann Colwell, Meredith Artley and Dorrine Mendoza contributed to this report. The story was written by Greg Botelho.