According to a social media post, Rep. Sean Casten mourned the loss of his 17-year-old daughter on Wednesday and said the teen died peacefully in her sleep.

The Illinois Democrat released a heartbreaking statement that said his oldest daughter, Gwen Casten, went to bed Sunday night and never woke up.  

“There are no words to describe the hole in your heart when a child dies,” the congress member said in a statement from himself, his wife, and his second daughter.

His office announced Gwen’s passing in a short statement Monday but provided no further information at the time.

“This morning, Congressman Casten’s beloved daughter, Gwen (17), passed away. The Casten family requests privacy, and we will be issuing no further comment during this heartbreaking time.”

The NY Post reported that Casten said Gwen, his wife Kara and younger daughter Audrey had dinner together as a family that night, Sunday, and then Gwen went out with friends for a few hours. After she returned home, she said goodnight to her parents, texted a friend to make sure she got home OK, and went to bed. She never woke up.

Casten said the only thing he and his family knows about her death is that it was peaceful.

Just 10 days before her death, the congress member recognized his daughter’s work organizing a “Stop the Bleed” training at her school in a broadcast interview.

Casten and his family thanked everyone who reached out with condolences and support.

“To all asking what they can do, we ask only that you live your lives as Gwen lived hers,” he said. “Savor the moments. Use every ounce of energy you have to ensure a better, more tolerant, more generous, more loving tomorrow. Not because you know that your tomorrow will come, but because you know that someone else’s will.”