Molly Martens and her father Tom have been found guilty of the second degree murder of Limerick man Jason Corbett.
The jury in trial in the US returned their verdict in the last half hour.
The 39-year-old was found beaten to death in the bedroom of their home in North Carolina two years ago.
The pair had claimed they acted in self defence in fear for their lives.
The jurors had the option of finding them guilty of second-degree murder, voluntary manslaughter or not guilty.
The difference between second-degree murder and voluntary manslaughter is that second-degree murder requires malice.