A statement from Mexico's Ministry of Foreign Affairs "categorically rejects claims to the effect that Mexican authorities are not doing enough to find" David Hartley.
Hartley's wife, Tiffany, says she and her husband were riding Jet Skis back from Mexico on Sept. 30 when they were attacked by Mexican pirates in speedboats who opened fire and shot David Hartley in the back of the head. Tiffany Hartley has said she tried to rescue him when he fell into Falcon Lake, but that she fled to U.S. waters as the pirates continued shooting.
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U.S. Rep. Henry Cuellar said Friday that while no evidence has caused investigators to question her story, the disappearance is mysterious.
"My question is, OK if he had a vest, why is the body not floating? We asked the Coast Guard, if he had a Jet Ski, would that Jet Ski be floating somewhere around? Our Mexican friends have said they've been searching around, they've even used a helicopter. If you have a general idea of where that is, why is the body not floating? Why is there not a Jet Ski?"
Cuellar went on to say "the bad guys could look at the Jet Ski as an asset that they could take" and that Zapata County Sheriff Sigifredo Gonzalez "does have an eyewitness, a person that did see her coming in with a boat chasing her, so we have to rely on law enforcement officials."
Gonzalez said the investigation so far has indicated Tiffany Hartley is telling the truth.
"Our information is indicating that the witness is reliable, the witness is truthful," he said. The possibility the witness is not telling the truth "is always there, but the probability is very, very, low," he said.
Evidence corroborating Tiffany Hartley's story includes a tiny smear of blood on her life vest, Gonzalez said.
"Other evidence has surfaced," he said. "I'm not at liberty to discuss it at this time, but it does indicate that she had nothing to do with" David Hartley's death.
Falcon Lake is a dammed section of the Rio Grande, 25 miles long and 3 miles across. Pirates have robbed boaters and fisherman on the Mexican side, prompting warnings by Texas state officials, but Hartley's death would mark the first violent fatality on the lake.
The foreign ministry's statement said the federal attorney general's office has opened an investigation based on Tiffany Hartley's testimony to Mexican consulate officials in McAllen, Texas, where she lives.
In the Hartleys' native Colorado on Friday, about 100 friends, relatives and supporters rallied outside the Mexican consulate in Denver. David Hartley's sister, Nikki, said it's hard to know what's happening across the border.
"We'd like to believe good people are down there but there's so much corruption, it's hard to have much faith that what you're being told is the truth," she said. But she later said she was encouraged after meeting with consulate officials who promised an open door policy to answer family questions.