Gabe Watson, the man recently put on trial for his wife's 2003 honeymoon drowning death, said he was "still going through the grieving process" when he used bolt cutters to remove flowers from his wife's grave.
"I mean, it definitely wasn't my finest hour," Watson told "20/20" co-anchor Elizabeth Vargas in an exclusive interview that marked the first time Watson has spoken to the media.
"I (had) just been accused of murder... I was still dealing with the death of Tina. I wasn't thinking clearly on everything that I did," he said.
Last week, an Alabama judge dismissed the murder charge against Watson, whose case garnered headlines in the U.S. and Australia, the site of his ill-fated honeymoon trip. Tina Watson -- the former Tina Thomas -- had been married to Gabe Watson for just 11 days when she drowned while they were scuba diving at the Great Barrier Reef.
Gabe Watson said his wife panicked and knocked his mask off, leaving him unable to help her. Watson, who had been nicknamed the "honeymoon killer," went on to serve 18 months in an Australian jail after pleading guilty to a negligent manslaughter charge for failing to save his wife.
"I pled guilty to... basically not rendering the proper aid, not saving my dive buddy," he told "20/20."
Though Tina Watson's death was originally ruled an accident, Australian authorities began investigating Gabe Watson in connection to his wife's death at the behest of Tina Watson's family.
The Thomas family, who say they were never close with Gabe Watson, grew suspicious of their then-son-in-law after Tina's father, Tommy Thomas, received a phone call from an experienced diver who was on the couple's diving trip. The diver, Ken Snyder, told Thomas he didn't believe Gabe Watson's story about how his wife died.
Thomas went on to pursue a crusade to have Gabe Watson investigated for murder, ultimately resulting in Gabe Watson's 2009 negligent manslaughter plea in Australia. His U.S. murder trial began and ended earlier this month.
In the U.S., prosecutors alleged Gabe Watson had turned off his wife's air supply -- an accusation Watson said he was "dumbfounded" by.
"It was hard to imagine that -- that there's someone out there that thinks that-- that I did this," he said.
The judge who dismissed the U.S. murder case against Watson cited a lack of evidence, but prosecutors later said that certain decisions by the judge weakened their case, including his refusal to allow jurors to see surveillance footage of Watson at his wife's grave, according to the Associated Press.
The footage showed Watson using bolt cutters to remove a flower display placed by Tina Watson's family. The Thomas family has said they chained the flowers to the grave site because Gabe Watson had removed other flowers from the site in the past.
Watson partly attributed his actions to grief.
"I was still going through the grieving process. There was still all kinds of stuff going on that -- it made me act different ways," he said. He conceded, "I'm not saying that what I did was good in any way."
But Watson also suggested that Tina Watson wouldn't have wanted that particular flower arrangement, which he said was made of plastic.
"When I would go out to Tina's grave I always left fresh flowers," he said. "And it struck a nerve with me that what I considered, and what I think Tina would have considered, big, gaudy, plastic arrangements that would sit out there and get faded in the sun."
Watson said he couldn't understand what removing the flowers had to do with Tina Watson's 2003 drowning.
"I don't understand what that has to do with what happened in '03. This was a year or two later -- I can't grasp the relevance of that to Tina's death," he said.