Brent King said in a letter posted Friday on the website chelseaslight.com that he, his wife Kelly and 13-year-old son Tyler will move next month to Naperville, Ill., where they lived for 10 years before moving to the San Diego suburb of Poway in 2007.
Convicted sex offender John Albert Gardner III pleaded guilty to King's murder, along with the February 2009 killing of 14-year-old Amber Dubois. He was sentenced last month to life in prison.
The family says it wants to return to a place where Tyler can grow up without the added attention that comes from being the brother of a well-known murder victim.
"It's really difficult for him to grieve out here and mourn the loss of his sister because it's such a public experience for him," Kelly King said Friday in an interview with the San Diego Union-Tribune. "It's not normal for him and he's had so much of his childhood taken away from him by losing Chelsea. We needed to do what's best for him."
Brent King said the family had decided to sell their home after getting an unsolicited offer before Chelsea's disappearance, but had originally intended to stay in Poway.
He said the decision to leave was very difficult because of the way the community has embraced the family.
"We have experienced the deepest pain a family can endure, and you in return have given us the deepest outpouring of unconditional love and support we could imagine," Brent King wrote.
King said the family will keep a residence in the San Diego area and return often.
Brent and Kelly King have been leading a campaign for "Chelsea's Law," which would allow life sentences for some convicted child molesters in California and lifetime electronic monitoring of others. The bill has cleared the state Assembly and is now before the Senate.