Texas Department of Public Safety Director Steve McGraw is scheduled to testify. So is McAllen police Chief Victor Rodriguez and Zapata County Sheriff Sigfedo Gonzales.
Zapata County is where an American tourist raced to shore last year after she said Mexican pirates ambushed she and her husband on Falcon Lake. Her husband's body wasn't found.
Officials from the Department of Justice, the Department of Homeland Security and Arizona's attorney general office are also set to testify.