A Fort Hood-based soldier has been missing for about a week since telling family members he was heading to a Texas border town, and the FBI says the Army was told the missing private had been kidnapped, the soldier's brother said Tuesday.

The family of Pfc. James Gonzalez, 24, last saw him July 11 at his mother's house in Robstown, near Corpus Christi, said his older brother, J.C. Gonzalez. James Gonzalez said he was headed to Laredo that afternoon to hang out with friends before returning to base July 13, his brother said.

LIVESHOTS BLOG: What Happened to Private Gonzalez? >>

But on July 13, Gonzalez's commander called looking for the private. Later that day, the FBI called the family to say that the Army had received a call saying Gonzalez had been kidnapped. The caller demanded $100,000 and the withdrawal of all troops from the border.

About 575 National Guard troops remain on the border, but thousands that had been patrolling the area withdrew last year.

The FBI referred questions to the Army, which is leading the investigation.

Christopher Grey, chief public affairs officer for the U.S. Army Criminal Investigations Command in northern Virginia, said the Army was cooperating with local, state and federal law enforcement agencies in the search for Gonzalez. Grey said the Army would not discuss details of the case, including whether it received a ransom call. The Army had issued an advisory in the border region asking people to be on the lookout for Gonzalez and to contact local law enforcement with information on his whereabouts, Grey said.

J.C. Gonzalez said his brother was familiar with the border city of Laredo and had not mentioned any plans to cross into Mexico, directly across the Rio Grande. For the past week his cell phone has gone straight to voicemail, he has not logged into his MySpace Web page and authorities have not been able to track his car, a 2006 BMW, which was fitted with a tracking device, said J.C. Gonzalez.

If Gonzalez was going to take off, "he would have told somebody," his brother said. "It's not like him at all."

James Gonzalez's decision to join the Army about a year and a half ago surprised his family, but they supported the decision, J.C. Gonzalez said. It seemed to be a good change for him.

"He was pretty happy," his brother said. "He had a house, a car and had taken that step to manhood. He was enjoying himself."

The family says it has been frustrated so far by the Army's response.

"We don't feel the Army is taking it as seriously as we are," J.C. Gonzalez said.

Gonzalez was awaiting trial this fall on misdemeanor charges stemming from an argument with his girlfriend. His brother said that situation was being handled and would have been no reason for him to disappear.