Authorities say a Minnesota mother and her cancer-stricken son refusing chemotherapy were in California as recently as Tuesday and might be going to Mexico to get treatment.
Authorities say the tip about Colleen Hauser and her 13-year-old is based on "reliable information."
Brown County Sheriff Rich Hoffmann says authorities think the pair is somewhere between Los Angeles and the Mexican border, but he says law enforcement have not had contact with them. Hoffman says it's believed the pair is heading to an area just south of San Diego.
The Hausers allegedly fled New Ulm, Minn., after a court-ordered medical exam showed Daniel's Hodgkin's lymphoma had worsened.
Hodgkin's lymphoma is considered highly curable with chemotherapy and radiation.
Authorities also believe they could be with Billy Joe Best, a man ran away to avoid chemotherapy more than a decade ago in Massachusetts.
In 1994, a 16-year-old Best ran away to avoid having more chemotherapy to fight his Hodgkin's disease. He returned after three weeks in Houston when his parents promised they would not force him to have the treatments.
Best has claimed his cancer was cured by natural remedies.
His parents, Sue and Bill Best of East Bridgewater, Mass., did not immediately return a phone message.
A crime alert said the Hausers might be with Best, or Susan Daya, also known as Susan Hamwi, a California attorney who accompanied them to a medical appointment Monday.
Daniel Hauser has been entered into the network of National Missing & Exploited Children, said Brown County Sheriff Rich Hoffman at a press conference Tuesday afternoon.
"I just wish we could get to Colleen and tell her to come in," Hoffman said. "This is not going to go away. It's a court order."
Colleen and Daniel Hauser were supposed to attend a court hearing Tuesday, but never showed up.
Daniel's father, Anthony Hauser, said he does not know where his wife and son are.
He said he last saw his son Monday morning, and he saw his wife only briefly that evening when she said she was leaving "for a time."
"I'd like to tell them to come back and be safe and be a family again," the boy's father, Anthony Hauser said during an interview posted on the Web site of KARE 11 Minneapolis-St. Paul Wednesday.
Sometimes she reacts real quickly at things," Hauser told KARE 11, referring to his wife. "She gets excited easily."
Brown County District Judge John Rodenberg issued an arrest warrant Tuesday for Colleen Hauser and ruled her in contempt of court. Rodenberg also ordered that Daniel be placed in foster care and immediately evaluated by a cancer specialist for treatment.
Officials distributed the arrest warrant nationwide. Hoffman said Tuesday that investigators were following some leads locally, but declined to elaborate. In an interview in Wednesday's editions of the Star Tribune of Minneapolis, Anthony Hauser said he knew places where his wife might have gone though he did not know where she was.
He said he and his wife had a plan for Tuesday's hearing and he was a "bit disappointed" she didn't follow it. "We were going to present a treatment plan to the court. If they didn't go with it, we would appeal it," he told the newspaper.
Daniel quit chemo after a single treatment. With his parents, he opted instead for "alternative medicines," citing religious beliefs. That led authorities to seek custody. Rodenberg last week ruled that Daniel's parents were medically neglecting their son.
Anthony Hauser also says he isn't against chemotherapy "if it's a necessary thing," but thinks doctors use it too much.
He said he thinks his wife just got scared when they got the results of the X-ray on Monday, and thought Brown County authorities would use it to try to get custody of Daniel.
"It's just my opinion, but I think she figured that because of that X-ray she feared they were going to take him," he said.
The Hausers are Roman Catholic and also believe in the "do no harm" philosophy of the Nemenhah Band, a Missouri-based religious group that believes in natural healing methods advocated by some American Indians.
Colleen Hauser testified earlier that she had been treating his cancer with herbal supplements, vitamins, ionized water and other natural alternatives.
The founder of Nemenhah, Phillip Cloudpiler Landis, said it was a bad idea for Colleen Hauser to flee with her son.
"She should have gone to court," Landis said. "It's how we work these things out. You don't solve anything by disregarding the order of the judge."
And Anthony Hauser now agrees that Daniel needs to be taken back to a doctor for re-evaluation for the best treatment, said Calvin Johnson, an attorney for the parents.
The family was due in court Tuesday to report the results of a chest X-ray and their arrangements for an oncologist. But only Daniel's father appeared. He told Rodenberg he last saw his wife Monday evening.
"She said she was going to leave," Hauser testified. "She said, `That's all you need to know.' And that's all I know."
He said Colleen Hauser left her cell phone at their home in Sleepy Eye.
The family's doctor, James Joyce, testified by telephone that he examined Daniel on Monday, and an X-ray showed his tumor had grown to the size it was when he was first diagnosed.
"He had basically gotten back all the trouble he had in January," the doctor said.
He said Daniel was at risk of substantial physical harm and needed immediate action.
Daniel was accompanied to the appointment by his mother and Daya.
Joyce testified that he offered to make appointments for Daniel with oncologists, but the Hausers declined. He also said he tried to give Daniel more information about lymphoma but that the three left in a rush.
"Under Susan Daya's urging, they indicated they had other places to go," Joyce said.
Daya did not immediately return a page left on her cell phone Tuesday by The Associated Press. Her voice mailbox was full. The court also tried to reach her during the hearing, but got no answer.
In his ruling last week, Rodenberg wrote that he would not order chemotherapy if Daniel's prognosis was poor. But if the outlook was good, it appeared chemotherapy and possibly radiation would be in the boy's best interest, he wrote.
Daniel's lymphoma was diagnosed in January, and six rounds of chemotherapy were recommended. He and his parents sought other opinions, but the doctors agreed with the initial assessment.
State statutes require parents to provide necessary medical care for a child, Rodenberg wrote. The statutes say alternative and complementary health care methods aren't enough.
He also wrote that Daniel, who has a learning disability and cannot read, did not understand the risks and benefits of chemotherapy and didn't believe he was ill.
Daniel testified he believed the chemo would kill him and told the judge in private testimony unsealed later that if anyone tried to force him to take it, "I'd fight it. I'd punch them and I'd kick them."
The Associated Press contributed to this story.