David Hartley's wife said pirates shot and killed her husband right before her eyes while they were both jet skiing on a lake near the Mexican border.
But police in Mexico said they have no evidence the attack took place.
They're now wondering if Hartley's wife could be behind the murder.
Hundreds gathered to celebrate the life of Hartley on Wednesday. His family continues to cope with his death and the disappearance of his body.
"It shouldn't be that hard to get him home," said Hartley's mother, Pam.
Hartley and his wife were at Falcon Lake, a reservoir on the U.S.-Mexico border.
Hartley's wife, Tiffany, said the two were ambushed by Mexican pirates.
Tiffany Hartley escaped, but her husband did not.
In a call with a 911 dispatcher, Tiffany Hartley is heard saying he was shot "in his head."
Nearly a week later, Hartley's body is still missing.
Mexico's ministry of foreign affairs issued a statement saying the country, is "committed to the investigation of those acts."
They said they've been in contact with the U.S. to coordinate the search and recovery of Hartley's body.
However, ABC News visited the area where Hartley said the shooting happened and saw no sign of any search efforts.
Mexican police in the Falcon Lake area have voiced doubts about her and implied she might have a role in her husband's disappearance.
"I would never even think about hurting my husband," she said."I loved him."
Texas Gov. Rick Perry said he personally contacted the president of Mexico to give him 48 hours to report back regarding the search efforts, and hopefully news about Hartley's body.
Perry said this incident is a sign the drug wars in Mexico are putting Americans in the crosshairs.
Napolitano said she has been assured that local officials in Mexico are searching for Hartley's body.