The former Kop boss, now at Inter Milan, claims that the club's managing director's arrival last summer was responsible for the dramatic change in fortunes that saw the team finish seventh last season after battling Manchester United for the Premier League crown a year previous.
Benitez, who has been roundly criticized in some quarters for Liverpool's on field plight, believes that the blame for its demise lies with Purslow, who was instrumental in ousting former owners George Gillett and Tom Hicks last week in the High Court.
"I prefer not to talk about this because I feel sorry for the fans," he said.
"I was really sad for them and after the defeat the other day.
"We have a saying in Spanish that says 'white liquid in a bottle has to be milk. This means that after 86 points and finishing second in the league, what changed? The Americans. They decide and choose a new managing director [Purslow] and everything changed.
"The managing director is involved in all the decisions. New lawyer, new chief of press, new manager, new nine players, new medical staff, new fitness coaches. They change everything, so they change managing director then we change everything that we were doing in the past.
"If you ask me what's going on it's simple - they changed some things and by the end they changed everything. White liquid in a bottle - milk. You know who to blame."
I feel real sorry for Rafa, he can't even enjoy being a manager elsewhere because he just constantly gets questioned about Liverpool. That being said, I MISS YOU RAFA. WHO WOULD HAVE THOUGHT I WOULD MISS SEING THIS: