U.S. Rep. Sean Casten is mourning the death of his 17-year-old daughter.
The Democrat from Illinois said his daughter, Gwen, was a happy and healthy teenager who was preparing to attend the University of Vermont.
Casten said he last saw his daughter alive on Sunday night. He said she had gone out with friends after dinner with the family.
Casten said she returned home, texted a friend to make sure she got home OK and then didn't wake up the next morning.
"The only thing we know about her death is that it was peaceful," Casten said in a statement.
The congressman urged people to savor every moment they have with their loved ones.
"Use every ounce of energy you have to ensure a better, more tolerant, more generous, more loving tomorrow," he said. "Not because you know that your tomorrow will come, but because you know that someone else's will."