Our Team

Tara-Leigh Cobble

D-Group Founder & CEO

Her earliest memory is learning John 3:16 from her mom, shortly before her brother led her to Christ. Despite an early introduction to Christianity, she wasted years coasting on the second-hand information she learned from others. In 2008, through the gentle encouragement of a friend, she read all the way through the Bible for the first time. That changed everything. "I wanted and needed people alongside me in my pursuit of God -- people to hold me accountable for scripture memory and Bible reading and all the things that were bringing me so much newfound joy!" Out of that need, she started D-Group with a handful of strangers in a living room in 2009. She lives in Dallas, TX, where she has no pets or children - or anything else that might die if she forgets to feed it.

CALLIE
SUMMERS

Executive
Director

JOELLE
SMITH

Logistics
Manager

She grew up in a Christian home with loving parents, but her faith became her own in college. Her hunger for the Word of God flourished and she discovered the power of Christian community and discipleship relationships as catalysts for spiritual growth. A native Texan, she loves the beach and the mountains, and enjoys hiking, camping, and hammocking. She is a voracious podcast listener and book reader. She is excited to join staff and is thrilled to be used by God to strengthen His kingdom! Callie is a member of Watermark Community Church in Dallas.

Though raised in the church, her life didn’t always reflect Gospel transformation. At a low point in her early twenties, two women approached her on the beach to remind her of God’s love for her. His pursuit of her never felt more real, and she began to fall in love with Him, the One who heals and restores. Shortly after that, she joined D-Group -- and even five years later, she still counts it among her best decisions. Her desire is to live out the words of John the Baptist: “He must increase, but I must decrease” (John 3:30). Joelle is a member of Providence Wesleyan Church in Summerville, SC.

RACHEL
MANTOOTH

Administrative
Coordinator

COURTNEY
VAUGHAN

Senior
Management

As the daughter of a Minister of Music, Rachel grew up being at the church "every time the doors were open." She became a Christian at the age of six but it wasn't until joining D-Group that she was truly challenged with the question, "Is what I believe deeply rooted in scripture or is it just what was taught to me as a child?" Through processing that question, God strengthened the truth of her faith and gave her a burning desire to know Him and His Word more. Rachel lives with her husband, Chase, and their two sons in Simpsonville, SC. They are members of Newspring Church in Greenville.

Although she has been a Christian since she was a young child, Courtney spent the majority of her Christian life checking the boxes she believed would make her a “good, moral Christian.” Since joining four years ago, The Lord has used D-Group to graciously show her more of Himself and to radically transform her concept of what it means to be saved by grace alone, through faith alone. She and her husband Dustin, along with their daughter Foster, split their time between Dallas and San Antonio. They are members of First McKinney Baptist Church.

LAUREN
MULFORD

Theology &
Content Director

BRIAN
SHAKLEY

Men's
Director

Lauren came to trust Christ with her salvation at the age of seven. She trained to be a professional ballet dancer with Ballet Magnificat and served as a missionary with them for three years traveling across the USA. She later went on to receive her bachelor’s degree in biology from the University of Texas at Arlington where she met her husband at a Bible study. D-Group catapulted her to “love God and love people” more than she had ever previously while maintaining doctrinal soundness. Her family of eight attends Hope Fellowship in Denton, TX.

Through leadership roles in various ministry organizations such as Youth for Christ and Campus Crusade for Christ, as well as continued involvement in local churches, Brian has developed a passion to see others cultivate a deeper faith through discipleship. Whether in youth ministry settings or peer-to-peer groups, he has seen the fruit of a structured, intentional approach to building relationships within the Church. He is married to Sissy, who is also a D-Group leader, and they currently live in Chattanooga, TN, where they are members of Calvary Chapel Chattanooga.