A Michigan teenager died five days after a bike accident that also killed her brother.

Karalee, 13, and Calvin Shepard, 12, were riding their bikes in Leroy Township, Mich., on Sept. 5 when they were hit by a Ford Explorer around 11:30 a.m. local time, WLIX reported.

Both children were wearing helmets as they rode along Grand River Avenue when they were struck by the SUV heading west near North Meech Road. Drugs or alcohol were not a factor, Michigan State Police said, WLNS reported. Calvin died at the scene, according to police, while Karalee was taken to a nearby hospital to be treated for life-threatening injuries.

The Ford Explorer driver was a 64-year-old woman who remained at the scene, police said, WLNS reported. An investigation is ongoing. There have been no arrests or charges announced.

On Thursday, Sept. 10, the children’s mother, Raquel Roark Shepard, announced in a Facebook post that Karalee died from her injuries.

Calvin and Karalee Shepard.Gofundme

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“Our hearts are broken beyond what we can put into words. We find comfort in knowing that Karalee and Calvin are together again and in the loving arms of our Savior,” Shepard wrote. “We are so grateful for every prayer, every message, and every act of love that has surrounded our family these past few days. Please continue to pray for our family as we begin to grieve the loss of two of our precious children.”

One funeral will be held for both children on Saturday, Sept. 12, Shepard wrote.

“We simply cannot bear the thought of saying goodbye to our children twice,” she wrote.

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On Tuesday, Sept, 8, Shepard remembered Calvin as “an amazing 12-year-old boy who approached life head-on.” He loved soccer, basketball, swimming, volleyball, and playing video games, she wrote.

“But one of the most important things about Calvin was the way he treated people. He was a really good friend. He noticed kids who were being teased or left out, and he would stand up for them. He wanted people to feel included, valued, and loved,” she continued. “He gave the best hugs, was generous with compliments, and wasn’t afraid to tell people how much he loved them.”

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The MSP is investigating the incident. PEOPLE reached out to the MSP for comment.

A friend of the Shepard family established a GoFundMe to support them. As of publication, it has already surpassed its goal and raised over $136,000.