Cavallari's brother Michael was found dead Thursday

Updated December 10, 2015 06:15 PM
Credit: Source: Instagram

Kristin Cavallari shared a heartfelt tribute to her older brother Michael Thursday, who was found dead nearly two weeks after he went missing.

“My heart is in a million pieces,” Kristin, 28, wrote on Instagram alongside a childhood photo of the pair. “Mikey, I could always count on you to make me laugh. You had such a good heart and will be forever missed. I’m at a loss for words but I know u are in a better place and finally at peace. I love u so much RIP.”

Utah police located Michael’s body at 10:30 a.m. Thursday. They had been searching for Michael, 30, since Nov. 27 after his 2014 Honda Civic was found abandoned five miles south of exit 175 on I-70, according to the Grand County Sheriff’s Office.

On Monday as officials continued the search, Kristin, 28, posted a photo of the pair on the beach as children.

“I appreciate all the concern, thoughts, and prayers that have been extended to me and my family,” she wrote. “We remain hopeful and I will share any news that we receive. I have such gratitude for all those that have shared their support.”

Kristin’s former The Hills costar and friend Audrina Patridge shared her condolences, telling PEOPLE: “That is such terrible news. My prayers go out to Kristin and her family.”

“She was always very protective of him,” the source says. “She was always trying to help him.”

After Michael’s body was discovered, Kristin thanks fans for their support.

“This is a very painful time and we are still processing it all. We kindly ask everyone please respect our privacy during our time of grieving,” she said in a statement to PEOPLE.