Administration
Father John Mosier
Pastor
Ordained June 6, 2019. Father Mosier attended Marquette University and served in the Marine Corps before entering seminary at Mount Angel. He also earned a degree from Saint Anselmo in Rome. He was ordained in Boise by Bishop Peter Christensen.
Father Celestine Agwu
Parochial Vicar
Ordained July 22, 2000. Father Celestine joined St. Mark's in August 2025 as Parochial Vicar. Originally from Nigeria, he served in Cameroon (4 years) and Canada (17 years) before joining the Diocese of Boise.
Mrs. Donna Gordon
Principal
Education: BA Business, BA Education, MS Educational Leadership
Mrs. Gordon began her formal educational journey at St. Paul's Catholic School in 2006. She has served as principal of St. Mark's since 2016, bringing both her business background and passion for Catholic education to the role.
Mrs. Erin Martin
Vice Principal
Education: M.Ed. — Educational Leadership
Experience: 19 years of teaching. Humor, strong relationships, and high expectations are essential to helping students grow academically and personally.
Mrs. Marie Anderson
Administration
Mrs. Rena Van Paepeghem
Administration
Mrs. Bobbi Rivas
Administration
Faculty and Staff
Mrs. Anita Martin
Preschool
Education: BA in Christian Counseling, Elementary Education Certification
Teaching at St. Mark's since 2018. Previously taught at a Catholic school in Wyoming for 6 years. "Teaching is both a profession and a ministry."
Mrs. Jacinda Johnson
Preschool
Mrs. Susan Jensen
Kindergarten
Education: BA — Boise State University, Adult Catechist Certificate — Gonzaga University
34 years of teaching and currently in her 28th year of kindergarten at St. Mark's. Inspired by Mother Teresa: "We cannot do great things, only small things with great love."
Mrs. Tiffany Lee
Kindergarten
Mrs. Brittany Brady
1st Grade
Education: BA Elementary Education with Emphasis in Spanish — University of Montana, Masters in Educational Leadership — Boise State University
Graduate of Sacred Heart and Bishop Kelly. "God gives everyone special talents and calls us to bear fruit with them."
Miss Julia Smith
1st Grade
Education: BA in Elementary Education — University of Idaho, Certified Literacy K-12
Currently pursuing a Masters in Curriculum and Instruction. Committed to fostering an inclusive learning environment where every student feels safe and heard.
Mrs. Elise Slattery
2nd Grade
Education: BA NYU in Literature with Creative Writing, MA Adelphi University in Elementary Education
Teaching Catholic education since 2006. "We create the climate — all children want to be seen and loved beyond what they can do at school."
Mrs. Melissa Pilch
2nd Grade
Education: BA Liberal Arts, Teaching Credential
Six years of teaching elementary education. Strives to create a nurturing yet structured environment where all students can learn the tools they need to be successful.
Mrs. Deanna Westmark
3rd Grade
Education: BA in Elementary Education, MEd with emphasis in ELL
Experience in grades 1st, 3rd, and 5th. Superpower: turning confusing moments into "Aha! moments" and making learning hands-on.
Miss Sarah Murray
3rd Grade
Education: BA in Elementary Education with Literacy Endorsement — Boise State University
11th year of teaching. Believes students are most successful when they feel supported, respected, and cared for.
Miss Mallory Eaton
4th Grade
Education: BA from Sam Houston State University, pursuing Masters in Education — University of Portland
From Texas, came to St. Mark's through the PACE (Pacific Alliance of Catholic Education) program. "Life with Christ is an adventure."
Mrs. Merrideth Dressler
4th Grade
Education: BA in Education, MA in Educational Management and Leadership
30 years dedicated to education. Favorite subjects: Reading and History. 9th year in the Diocese of Boise.
Mrs. Cheri Workman
5th Grade
Education: BA in Environmental Studies, MSed in Curriculum and Instruction
20+ years of teaching. Loves technology and teaching students 21st-century skills. "An investment in knowledge pays the best interest."
Mrs. Hillary Maltby
5th Grade
Education: BA in Psychology, MA in Education, Multiple Subject Teaching Credential
Has taught 3rd, 4th, and 5th grade. Teaching has always felt like her "career soulmate." She never feels like she's "going to work."
Miss Celeste Hatfield
Math & Art
Education: BA Math — Gonzaga University, Masters in Teaching — Santa Clara University
Seven years teaching in Catholic schools. "Hard work beats talent if talent never works hard."
Miss Ashley Huss
Middle School Theology & ELA
Education: BA in Theology — Holy Apostles College and Seminary
5 years teaching middle school, 6 years as youth minister, plus missionary work. "My job is to plant seeds; God's job is to make them grow."
Mr. Maximillian Groninger
Middle School
Education: BA in Business Administration
30 years of teaching in Catholic education. Has a heart to teach middle school students and a passion for forming student minds and souls.
Mrs. Nicole Schuette
Middle School ELA
Education: 6-12 English Teaching
23 years of teaching, the past 19 years at St. Mark's. Loves reading, sharing books with kids, and teaching writing.
Mrs. Wendy Behrend
Middle School Religion & Science
Education: BS in Physics, BS in Education
30 years teaching in Catholic schools. Loves incorporating dramatic arts in the classroom. Became a teacher to pass on the Catholic faith to the next generation.
Señora Rosa Mari Arrubarrena
Spanish
Education: BA from the University of Idaho — Spanish major, Business minor, ESL teaching certificate — USC
Teaching Elementary Spanish at St. Mark's since August 2016. Previously taught at Bishop Kelly and St. Joseph's Elementary.
Mrs. Kathryn Arentz
Pre-K Assistant & Art
Education: BFA in Fine Arts — Otis College of Art and Design
Over ten years teaching drawing, painting, sculpture, and graphic design to students of all ages. "If you're able to share your talents with others, it's not work. It's your calling."
Mrs. Katrina Hauck
Religion
Education: BA in Psychology — Whitworth University, Graduate Certificate in Family Engagement in Education — Harvard University, Catechist Certification
Strives to create a calm and positive environment. "I want to teach children about the unending and unconditional love that Christ has for them."
Mr. Paul Holm
Math Aide
Education: BA Mathematics — University of Nebraska, BA Accounting — Boise State University
Former actuary and tax accountant. "Mistakes are great if you learn from them." Enjoys working one-on-one with students.
Mrs. Mary Larrinaga
Preschool
Education: BA in Communications
"Every child is worthy of my attention, love and patience." Passionate about early childhood development and seeing the wonder of little minds.
Mrs. Julie Whitescarver
Instructional Aide
Education: BA in Sociology — Seattle Pacific University
Her heart is to uplift and support students and aide teachers in their daily work. "My prayer each day is that I can offer a joyful, supportive, and hardworking spirit."
Mr. Allen Rossi
Facilities
An integral part of the St. Mark's community since 2016. Always making sure the facilities are in top shape — and a fan favorite amongst the students.
Specialists
Dr. Joe Lipetzky
School Psychologist
Education: BS in Social Research, MA Scripture, MA Clinical Psychology, Psy.D. Clinical Psychology
37 years as a therapist, teacher, and presenter. Methods include Thomistic Psychology, Attachment Therapy, Cognitive Therapy, and Behavior Therapy.
Mrs. Sarah Lynch
School Counselor
Education: M.Ed. School Counseling, B.S. Elementary Education K-8
11 years teaching in Catholic schools, 4 years as school counselor at St. Mark's. "Every child deserves to feel understood, supported, and capable of growth."
Mrs. Melissa Brady
Reading Specialist
Education: BSED Elementary Education — University of Missouri, MA Literacy — Boise State University
19 years of teaching, 10 at St. Mark's. "I became a reading teacher because my own child struggled with reading and I wanted to find ways to help all children learn."
Nurse Sherry Placido
School Nurse
Education: Early Childhood Development, Certified Nursing Assistant, Heart Saver CPR Instructor
Nearly 20 years with Saint Alphonsus. Over half those years in the School Health Program as well as direct patient care in the hospital.
