( CNN ) -- Twelve suspected members of the Zetas drug gang and a member of Mexico 's Navy were killed in a shootout on an island in a lake that straddles the U.S.-Mexico border , authorities said Monday . The Mexican Navy said the shootout occurred Sunday on Falcon Lake , located between Texas and the Mexican state of Tamaulipas , after troops patrolling the area spotted a camping area on an island . The suspected drug traffickers used the island for storing marijuana to be transported by boat to the United States , the Navy said in a statement . After the shootout , the Navy said it seized guns , ammunition and bullet-proof vests from the island . Falcon Lake drew the attention of law enforcement authorities on both side of the border last September after an American man on a personal watercraft was reportedly ambushed by attackers and shot in the head . 2010 : 'He took a bullet for me , ' Falcon Lake victim 's wife says . Tiffany Hartley told police that she and her husband were riding water scooters on the lake on September 30 when they were attacked . Her husband 's body has not been found , and the case has remained unsolved . `` It did n't happen in the United States , '' said Zapata County , Texas , Sheriff Sigifredo Gonzalez . Suspects in Falcon Lake killing identified . And Mexican authorities , he told CNN last month , have `` somewhat of a zero solvency rate , and a zero conviction rate . '' `` So unfortunately , this case may remain open forever , even though the information and the evidence may be there , '' according to Gonzalez .
Mexico 's Navy says a shootout occurred around an area used to store marijuana . Two suspected members of the Zetas drug gang and a member of Mexico 's Navy are killed . Falcon Lake is between Texas and the Mexican state of Tamaulipas . It drew attention last year after an officer was reportedly shot there .