Staff and Elders



Tim Park
Lead Pastor

Tim grew up in Orange County and received his B.A. in Sociology from UCLA (go Bruins!) and his Master of Divinity from Talbot School of Theology. Tim is passionate about seeing people’s lives transformed by the Gospel. Tim and his wife, JoAnn, have two children, Andrew and Amanda. Tim enjoys finding new places to eat and running marathons.


Kevin Ahn
Youth Pastor

Kevin was born and raised in Orange County, CA. He lived in Chicago, IL for 8 years where he served in a variety of youth ministry contexts, received his B.A. in Biblical Studies from Moody Bible Institute and M. Div from Trinity Evangelical Divinity School, but most importantly he met and married his wife Kelly. In his free time Kevin enjoys watching the Dodgers and Lakers, practicing Brazilian JiuJitsu, and finding new food recipes on YouTube. But his ultimate passion is youth ministry where he gets to pour into the next generation of the church and see students wrestle with and understand the Gospel.


Melissa Lobozzo
Children’s Ministry Director

Melissa was born and raised in Lakeland, Florida. She graduated with a B.A. in Elementary Education from the University of Florida. She is married to Tony, and has three children, Kailan, Sophia, and Abriana (Bri). Prior to moving to California, Melissa and her family created and managed a foster care ministry, uniting siblings in foster care who were separated in different foster homes. Melissa is passionate about teaching children the love of Jesus and the unique gifts they have been given to serve and love others.


Linda Merrill
Children’s Ministry Assistant

Linda is a Southern California native who moved to Diamond Bar in 1982 when she married her husband Dennis. They have 3 children and 6 grandchildren. Linda has been involved in early childhood education since college. She began teaching Sunday School in 1990, and since coming to EFree in 2007 has been an active participant in our Children’s Ministry as a Sunday School teacher and the VBS Bible Teacher coordinator. She joined our staff as Children’s Ministry Assistant in 2017 and stepped in as the Interim Director in September of 2021. Linda feels blessed at the opportunity to combine her love for the Lord and His Word, and her love for teaching children, and to pour that combination into the children and their families here at EFree Diamond Bar.


Tim Callahan
Junior High Director

Tim grew up in the Bay Area with a large family before moving to Diamond Bar for college. After moving he got connected to Efree and soon became the Children's ministry intern. He then felt God calling me to work with the Jr. High ministry.
"Working with Jr. High students is exciting because it is one of the most pivotal times in a persons life."
While living in Southern California, he met and married his beautiful wife Alexis.
His hobbies include, traveling, following sports, exploring the outdoors and finding new coffee shops.


Jim Wes
Director of Shepherding Ministries

Jim was born in Philadelphia and moved to San Diego for Jr High. He was later trained as an engineer at UC San Diego. While working in Defense R&D and working with church high school students, he met his sweetheart, Cindy. Together, Jim and Cindy raised their four kids at EFree Church and continue to serve in many areas of ministry. They are passionate about connections, worship music, and the church caring for the church. Weekends may find them folk singing or at the pool with their four grandkids.


Eddie Lee
Worship Arts Director

Eddie was born and raised in Los Angeles and moved to Diamond Bar at the age of 16. He began attending EFree Diamond Bar with his family in 2014 and began serving on the worship team in 2015. Eddie has a passion for music and worship and is honored to be part of the EFree staff in the role of Worship Arts Director. Eddie and his wife, Susy, have four boys, Lennon, Cullen, Madsen and Julian. Eddie loves spending time with his family, enjoys watching movies/television shows, and listening to a variety of music.


Mike Scaccia
Facilities Manager

Mike is our Mr. Fix-It. With a smile, he makes sure that everything in our facilities is as it should be. Whether it is room setup, repairs, enhancements, maintenance, or IT support for the technologically disinclined, Mike is always there to help. Mike is married to Amy, and has two children: Phoebe and Caden.


Mona Hwang
Finance Manager

Mona was born in Pittsburgh, Pennsylvania and moved to Southern California during elementary school. She graduated with a B.A. in Mathematics from UC Berkeley (Go Bears!). She is married to David, and has three children, Elizabeth, Joseph and Alexander. Mona is passionate about sharing and showing God’s love with family, friends and community and feels blessed to use her background in finance to oversee EFree’s finances. Mona also serves in the Children’s Ministry teaching the 4th and 5th graders.


Gail Laurie
Adminstrative Assistant

Gail was born in Montebello and grew up in Monterey Park, California. After graduating high school, Gail immediately went to work in Los Angeles at Security Pacific Bank in the Security Division. In 1980, she started her own secretarial service called “Surrogate Secretary” and accepted the Head Secretary position from Chevron Oil Field Research Co. in 1982. At EFree, Gail is an administrative assistant insuring a smooth flow of communication from top to bottom. She enjoys seeing God at work in her small group, and Adult Bible Fellowship. In her free time she enjoys traveling, going to the beach and river, and spending time with friends. Gail is married to Stuart and has three adult kids, and two grandchildren.


Elaine Yee 
Adminstrative Assistant

Elaine is passionate about our church and about bringing excellence to everything we do. She served our church in a number of volunteer opportunities before coming on staff, including serving as our Deaconness of Fellowship. Elaine holds B.S. in Human Resources from California State Polytechnic University, Pomona. She also has a lot of project management experience. Elaine is married to Thomas, and they have three children.


Mark Hopper 
Pastor Emeritus

Pastor Mark Hopper served as the Lead Pastor at EFree Diamond Bar from June 1988 to August 2015. He is a graduate of Dallas Theological Seminary with his Th.M and also holds degrees from Arizona State University and the University of Arizona. If you step foot on our campus, you will without a doubt be greeted with a warm smile and friendly conversation from Pastor Mark. He is gifted with a shepherd’s heart and cares deeply for the needs of our church family. In Mark’s spare time, he enjoys golfing, reading history books and spending time with his family.



John Hamel (Chair)

William Shih (Vice-Chair)

Nick Gonzalez

Bruce Biller

Ron Clark

Phil Meister

Tony Feng

Chuck Johnson

Tom Leininger