WASHINGTON — Improvised explosive devices, like those that have killed and maimed thousands of American soldiers in Iraq and Afghanistan, pose a growing threat across Texas and the United States, leading to calls for urgent cooperation between U.S. military experts and civilian law enforcement officers. Army Lt. Gen. Michael Barbero, director of the Pentagon's so-called Joint Improvised Explosive Device Defeat Organization, alerted Congress in classified testimony this month to the mounting IED threat at home. He also highlighted the challenges his team faces trying to train stateside law enforcement agencies to detect, disarm and defeat the devices. “The domestic IED...