In November 1761, an attempt by MacNaghten and his followers to abduct Mary Ann from a carriage on a family journey to Dublin Parliament and elope with her failed, when he shot and mortally wounded her by mistake. He was taken to Lifford Courthouse in Donegal, where a court found MacNaghten guilty of murder and he was sentenced to execution by hanging.
In November 1761, MacNaghten's attempt to abduct Mary Ann from a family carriage on the way to Dublin Parliament ended in disaster when he mistakenly shot and fatally wounded her. He was subsequently taken into custody at Lifford Courthouse in Donegal, where he was found guilty of murder and sentenced to death by hanging.