Samantha Spiegel, 19, claimed in a request for a restraining order against John Mark Karr that he made "ongoing death threats" and "threats of sexual exploitation to children" in e-mails and instant messages. The order was granted on April 19, but Spiegel's attorney said Karr has not been served because he could not be found.
Officer Alberto Esparza, a department spokesman, said Wednesday that Karr's "whereabouts are unknown."
"Our primary concern is the victim's safety," he said. "San Francisco police takes these threats very seriously and we're doing everything we can to continue the investigation and bring it to a close."
Spiegel told NBC's "Today" show that she had known Karr since she was 9, when he was a teacher at her school in San Francisco. She said they later became engaged.
Karr is now living as a woman.
Her attorney, Robin Sax, told The Associated Press that Spiegel reached out to Karr after he confessed to the death of 6-year-old child beauty queen JonBenet, whose body was found in 1996 in her parents' home in Boulder, Colo.
"She sought him out trying to reconnect, wanting to find out what happened to him," Sax said.
Things moved quickly to Karr contacting her hundreds of times a day, Sax said.
Spiegel also said Karr told her to help him recruit children, and that she thought about letting him meet her niece. Spiegel now says she was brainwashed, and that she's speaking out to help other potential victims.
"I think this is something I would have liked someone to do for me when I was in his grip," Spiegel said.
Karr drew international attention in 2006 with his arrest in Thailand over his bizarre, detailed confession into JonBenet's death, but DNA tests failed to put him at the crime scene.
He legally changed his name in Washington state to Alexis Valoran Reich in 2008, according to court documents.
Messages sent to the e-mail from which the threatening messages came were not immediately returned.
Sax said she believes Karr is running a website that includes his writings and statements, but it could not be confirmed that he was involved with the site. A phone call and e-mail to the site's administrator were not returned.
A hearing on whether to extend Spiegel's restraining order was postponed Wednesday until June 23.
(Copyright 2010 by The Associated Press. All Rights Reserved.)