article_snippet.sent: The man who allegedly killed his neighbour was believed to be suffering from dementia and alcohol abuse at the time of the horrendous murder in 2012, a jury has heard.
article_snippet.sent: Forensic psychiatrist Professor Paul Mullen examined Costa after the attack and believes there was evidence of the accused's state of mind declining in the lead-up to incident and also during the event, The ABC reported.
article_snippet.sent: I believe that at the time of the killing Costa brain was compromised by dementia and when you add to this alcohol that led to a confused state,' Forensic psychiatrist Professor Paul Mullen said. '
article_snippet.sent: Prosecutor Shane Drumgold suggested that Costa feigned Prosecutor Shane Drumgold failing memory while being interviewed by Professor Mullin - who denied these claims. '
article_snippet.sent: My view is that it was more likely than possible that Mr Costa was suffering a demented illness in the weeks, months and possibly years in the lead up to this event,' Prosecutor Shane Drumgold said.
article_snippet.sent: Costa's state of mind is critical to case, as .
article_snippet.sent: The jury can return a not guilty verdict  if Costa's unstable mindset at time of the attack can be proven.
highlights_snippet.sent: Experts says Costa suffered from dementia and alcohol abuse at the time .
  
highlights_snippet.sent: his also said there were signs of Costa's decline in the lead-up to incident .