The search may soon be expanded into Iowa for two missing children who investigators say may’ve been murdered by their father. Authorities across the Midwest are following the case of Sarah and Phillip Gehring, who were last seen on July 4th with their father in Concord, New Hampshire, where they lived. Manuel Gehring made a cross-country trip last week. It’s believed he left with the children, ages 14 and 11, but arrived in California without them — where he was arrested. Police say it’s a double-homicide case and there’s no chance the siblings are alive, but won’t elaborate. Gehring reportedly objected to a new custody arrangement with his ex-wife. Credit card receipts indicate Gehring made at least one stop in Iowa — at an unnamed convenience store in Iowa City — and traveled along Interstate 80 into Nebraska. So far, the search for the bodies of the boy and girl has focused on Ohio but nothing’s been found. As yet, Iowa officials have not been asked to begin a search. Jeff Stelzin, an assistant attorney general in New Hampshire, says anyone who saw anything unusual should call authorities.