Authorities have increased the reward for information that helps solve the mystery of what happened to two Border Patrol agents near Van Horn, Texas.
The FBI is now offering $50,000, and the state of Texas has added $20,000, for a total of $70,000.
What authorities know for sure is both agents suffered massive head injuries and were found in a culvert near Interstate 10. Agent Rogelio Martinez later died. His partner remains hospitalized.
The FBI has also launched a billboard campaign along the southwest border. Investigators want to hear from anyone who saw something between 10 p.m. and midnight on Nov. 18 while driving through Van Horn, Texas.