Halsey became the victim of abuse for the way he handled the confrontation between the two sides.
Some Liverpool fans believed that the sending off of Jojo Shelvey was harsh while Robin van Persie was booked for a similar offence later in the game. He also gave United a late penalty in the game which van Persie converted to take the points, again this was frowned upon by some Liverpool fans.
A tweet posted from an account named @johnwareing1 read: "I hope Mark Halsey gets cancer again and dies" while another from @lfcjohn259 read: "Mark Halsey should've died of cancer."
Both tweets were met with outrage.
Halsey was diagnosed with throat cancer in 2009 but returned to refereeing in March 2010.