As training camp began for the Kansas City Chiefs this week, they faced a heartbreaking situation because of the passing of one of their lifelong fans, Jessica Tangen, who died while attending the training camp on Sunday.

Mosaic Life Care, a healthcare company working in collaboration with Chiefs training camp, issued an official statement regarding Tangen's death on the same day.

"We are devastated to share that one of the Kansas City Chiefs' beloved fans, Jessica Tangen of Riverside, MO, passed away Sunday morning during practice at Chiefs training camp," Mosaic Life Care said.

"Jessica's family shared that she was a lifelong Chiefs fan and loved cheering for the team.

"Please join us in lifting up the grieving family with your thoughts and prayers."

What happened to Chiefs fan Jessica Tangen?

The company has not disclosed the official cause of her death, though it's worth noting that this NFL training camp coincided with a severe heatwave that affected the Western Missouri region in July.

Mosaic Life Care reported that their caregivers attended to Tangen's medical needs during the training camp, and they received support from the staff at Missouri Western and Buchanan County Emergency Medical Services (EMS).

An ambulance was stationed at the base of the hill near the Mosaic Training Fields, where the Chiefs were practicing.

The Chiefs are holding their 13th training camp at Missouri Western and, while practices are generally open to the public, reservations for tickets must be made in advance to manage the crowd size. Season ticket holders were given priority in booking their tickets.