A slashed car tire delayed Luca Principali's father just long enough for his mother and an accomplice to nab him from his Boise home, investigators said last week to persuade a judge to issue a warrant for her arrest for kidnapping.

The half-hour it took Anthony Principali to change his tire bought the time the kidnappers needed to nab the boy and leave a 14-year-old baby sitter so scared she didn't call police.

Though police officials won't reveal any new information about the case, court documents filed this week by Anthony Principali show why they are so sure his wife, Ekaterina, is behind the kidnapping.

About two hours after Luca was abducted on Aug. 19, Ekaterina Principali called Anthony Principali and told him she took the boy to teach the father a lesson and that she would return the boy later.

By then, police were at the apartment and Anthony Principali handed the phone to police Det. Mark Vucinich. When Vucinich told her to return the boy, the woman hung up.

Police were later able to track her cell phone to Jerome and then to Hazelton, which indicated she was most likely traveling east on Interstate 84.

That was 10 days ago, and the boy is still missing.

Anthony Principali filed for a divorce Aug. 18, requesting that the boy live with him but that the couple share custody.

He amended that request Aug. 26, asking for sole custody in light of the boy's kidnapping. Included was his own affidavit explaining what has happened with the family over the past several months and the police affidavit asking for the arrest warrant.

According to the documents, Ekaterina Principali had not seen Luca in more than a year, but she had been in phone contact.

She lives and works in Phoenix, but police found that she secretly checked into Boise's Cabana Hotel on Aug. 16. That's where investigators learned she was in a Dodge Grand Caravan with California license plates - the minivan that police and the public were asked to look for in an Amber Alert issued for the boy.

Anthony Principali has been Luca's sole caregiver since his wife moved from the family's former home in Rockford, Ill., to Phoenix in July 2008, the father said in the affidavit.

He said he encouraged his wife to visit Luca both in Illinois and in Boise, where he and the boy moved about eight weeks ago, but she never came to visit.

Boise police spokeswoman Lynn Hightower said the investigation is "very active" and that Boise police are working with several state and national agencies and following several leads.

"They are still very, very hopeful they will reunite Luca with his father," Hightower said.

Cynthia Sewell: 377-6428