Gabriel Z. Gaeta, 17, who was arrested Saturday, was ordered held Monday on $1 million bail. Authorities said he will probably be tried as an adult.
James Wright said Gaeta was a visitor at their home in the Steele Creek Mobile Home Park and played with his older children. He said he had tried to help the teenager, showing him how to make extra money by chopping wood.
"It's devastating. It almost would have been easier if it was a stranger," Wright told the Seattle Times.
Gaeta, a star wrestler at Olympic High School, has no previous criminal record.
Jenise was reported missing Aug. 3. Her parents said they had last seen her at bedtime the night before but waited until late in the evening the next day to call police because she frequently wandered off to play around the park.
Searchers found bloody clothing early in the week. On Thursday, Jenises's body was found in a wooded area.
On Friday, when FBI agents took a DNA sample from Gaeta, they found him "leaning against the wall, barely able to get out of bed and emotionally upset," a court document said.