Blackett's investigation centred around events following the first Test defeat in Auckland on June 14, after which a number of England players were accused of an alleged serious sexual assault at the team hotel.
David Strettle and Danny Care, both also of Harlequins, have been cleared of any misconduct in relation to allegations made against them - all three deny any criminal wrong-doing.
A club statement issued on Tuesday backed the trio, adding: "It has been a difficult time for them all as they have had to withstand a great deal of ill-informed and potentially damaging speculation about their behaviour.
"All three players have had exemplary disciplinary records in their rugby careers to date, and it was particularly pleasing to see Danny Care and David Strettle were entirely cleared.
"In the case of Mike Brown, he is fully aware that he should have returned to the team hotel at an earlier hour.
"Although a relatively minor misdemeanour, he fully accepts the sanction imposed and will now concentrate on regaining his place in the England team."



