Kim Kardashian is saying goodbye to her late aunt Karen Houghton.

Kardashian, 43, shared a series of throwback photos of Houghton via Instagram on Thursday, March 21. “🕊️I love you so much auntie Karen🕊,” the reality star captioned her post.

One snap showed a young Kim and older sister Kourtney Kardashian sitting with Houghton, while another pic showed Kim posing with her aunt in front of a Christmas tree. In one photo, Houghton stood with her mother, Mary Jo “MJ” Shannon, and Kim’s parents, Kris Jenner and Robert Kardashian.

Houghton, Jenner’s younger sister, died on Monday, March 18, at age 65. A cause of death has not been revealed.

“It is with the heaviest heart and deepest sadness that I share that my sister Karen passed away yesterday unexpectedly,” Jenner, 68, wrote via Instagram on Tuesday, March 19. “My heart aches for my mom MJ and my niece Natalie and I pray that God guides us all through this difficult time.”

Jenner went on to call her sibling “beautiful inside and out” and the “sweetest, kindest, the most sensitive and vulnerable and so so funny” person.

“She always felt grateful and thankful for her life and treasured her family and friends and especially her beautiful daughter,” the reality mogul continued. “Karen’s passing is a reminder that life is so short and precious, and tomorrow is never promised. We must tell those we cherish how much we love them. I love you my beautiful sister.”

Houghton’s daughter, Natalie Zettel, shared an Instagram tribute to her mom one day later.

“Dear Mommy, I can’t believe [you’re] gone,” Zettel wrote on Wednesday, March 20. “This doesn’t even feel real. I keep hoping that I will get to hug you or kiss you or hear your voice one last time. You were my best friend, my everything. The best mother a daughter could ever ask for and I’m so grateful to have had a mother like you.”

Zettel’s message was accompanied by a series of throwback photos of Houghton, including one of her cradling her daughter just minutes after she was born.

“You were the most kind, sweet, loving, giving, and caring soul,” Zettel continued. “You had the biggest heart. And I don’t know how to go on without you. It all happened so quick & I wasn’t ready for you to go.”

Karen and Jenner are the only children of Shannon, 89, and her husband, Robert “Bob” Houghton. Bob died in 1975.