Tigers manager Phil Brown is adamant he saw Spain midfielder Fabregas - who was out injured and did not play but came on after full-time to celebrate with his team-mates - spit towards Horton in the tunnel.
Brown told the Hull Daily Mail that he had now sent in his evidence to the FA as hard Horton and fitness conditioner Sean Rush.
"My evidence has gone in, Brian Horton's evidence has gone in and Sean Rush's evidence has as well. That is all that has been necessary as regards to us up to now," Brown said.
"There is an independent solicitor representing us and hopefully there will be no bias towards any one club.