A judge has barred the stepmother of a missing 7-year-old Portland boy from contact with her children and from access to firearms, further isolating her from the investigation into Kyron Horman's disappearance.

The boy's father, Kaine Horman, filed for divorce Monday from Terri Moulton Horman, citing "irreconcilable differences," and requested a restraining order, which was granted shortly after by a judge in Portland.

The couple were married in April 2007.

According to court documents made available Tuesday, the father had a new, undisclosed address as of three days earlier.

The restraining order was requested under terms of Oregon's Family Abuse Prevention Act. That document remained sealed Tuesday, but such petitions are required to cite instances of abuse, or attempted abuse, "with particularity," including dates, according to a guide compiled for the state's court system.

Terri Moulton Horman and her estranged husband have a 19-month-old daughter, and she also has a teenage son from a previous marriage.

Investigators have not named Terri Horman as a suspect in the Kyron's disappearance. They have said she's the last person known to have seen him before he vanished June 4.

In granting the restraining order, Judge Keith Meisenheimer said releasing that court document "will not risk compromising the effort to find Kyron Horman and related criminal investigations."

Although she and the boy's father put up a united front for the first three weeks, that has changed. A statement in support of the investigation was released Monday, but it was only signed by Kaine Horman, the boy's mother Desiree Young, and her husband, Tony Young.

Terri Horman was at the countryside home she had shared with Kaine Horman in the northwestern part of the city on Tuesday, but did not respond to reporters assembled outside.

Asked Tuesday about the divorce filing, sheriff's office spokeswoman Lt. Mary Lindstrand said it was "a personal matter between the parties, so we're not commenting on it."

Terri Horman told investigators that she last saw the boy after they attended an early morning science fair at his elementary school in a wooded area of northwest Portland. She said he walked down a hallway toward his second-grade classroom, wearing a "CSI" T-shirt and dark cargo pants.

Deputies have asked the public for information on Terri Horman's whereabouts on June 4. She has reportedly taken two polygraph tests.

During the search for Kyron, police have combed woods and fields near the couple's house and the school, and a large island in the Willamette River. A helicopter and divers helped ground teams in the search.