In a heartwrenching 911 call, Hartley tells the dispatcher that her husband has been shot in the head and that she is too weak to pull his body up onto her Jet Ski. She was forced to abandon him there.
Tiffany Hartley returned for the first time Wednesday to the location where she said her husband was killed last week.
"It was hard, just remembering everything about us going in to go take pictures and enjoying the sunny day and enjoying the nice weather," Tiffany Hartley, wife of missing David Hartley, told "Good Morning America" today, just hours after returning from the emotional trip.
Surrounded by a flotilla of police and politicians, Tiffany Hartley looked somber as she gazed at the water -- the last place she saw her husband alive.
In the days since the alleged attack, Hartley has defended herself from those who question the credibility of her story.
"It's hard to believe that they don't believe me, but it is a story that most people don't understand, that pirates would be on a lake, that the cartel[s] are taking over Mexico. It's a story that people don't understand unless they're on that border."
U.S. officials said they're prohibited from entering Mexican waters to search for the body.
In addition to President Obama, David Hartley's mother, Pam Hartley, has issued a public plea to Secretary of State Hillary Clinton, asking for aid in bringing her son's body home.
"He needs to come home and we're begging the Mexican government, the governor of Texas, President Obama," the man's mother, Pam Hartley, told "Good Morning America" Tuesday.
"To Hillary -- mother to mother -- help me bring my son home, please," she said, crying. "She's a mother, she would know."
David Hartley was a history buff. Tiffany Hartley, 29, said she and her husband dismissed warnings about crossing into the Mexican side of the lake so they could take pictures of a historic church. She said it had been some months since they had heard reports of pirates being on the lake.
According to Hartley, while they were making their way back to the U.S. border, the couple was approached by three boats of fully armed pirates, she said.
"David and I were racing back to the U.S., and they started shooting," she told "Good Morning America." "I looked back, and I saw that David had been shot, and I turned around to go get him."
Hartley said she tried as hard as she could to pull her husband onto her own Jet Ski to take him to safety, "but he's a lot bigger than me.
"You can't imagine how awful it was not being able to help him," she said.
Knowing her own life was in jeopardy, Hartley said she was forced to abandon her husband. She took her Jet Ski at top speed back to the U.S. shore and placed a panicked 911 call.
U.S. authorities have searched Falcon Lake on the American side, to no avail.
The state of Texas had warned boaters and fisherman as long ago as April to stay away from the Mexican side of the lake. Since then, the drug wars along the border have gotten more violent and there have been reports of more pirate encounters.
Falcon Lake, part of the Rio Grande situated directly on the Texas-Mexico border, has recently become a haven for the pirates, and there have been at least five reported run-ins with pirates on the lake this year, although this is the first reported death.