A federal magistrate Wednesday found probable cause to hold Terry Frank without bond while a grand jury hears evidence in the shooting deaths of two Navajo teenagers.

A secretary in the office of U.S. Magistrate Morton Sitver said no date was set for further action.She said Frank, 25, was charged with one count of homicide in the shooting death Friday of Eugene George, 18, and Irvin Harvey, 14.

Harvey's brother, Lewis, 17, and sister, Esther, 15, were hurt in the same shooting spree in the reservation community near Chinle, Navajo police said.

Officials have said an argument escalated into the violence that took the lives of George and Harvey.

Roger Dokken, an assistant U.S. attorney, said if the grand jury finds cause to indict Frank, it would return multiple counts of whatever type of crime was warranted. The initial complaint was a temporary charge signed in the field before Harvey's death, he said.

"I don't know if it's true in this case, but sometimes in a complaint they're just charged with one count because there's not a lot of room on the sheet of paper," he said.

Frank had appeared Monday after he was transported to Phoenix, and Sitver assigned a defense attorney, the secretary said.