The Trump campaign also faces accusations a speech by Mr Trump’s wife Melania on Monday was plagiarised.
Tuesday’s speakers focused almost exclusively on attacking Hillary Clinton, the likely Democratic nominee.
New Jersey Governor Chris Christie, a former prosecutor, held a mock trial for Mrs Clinton as the crowd chanted “lock her up”.
Mr Christie and others criticised Mrs Clinton’s use of a private email account while she was serving as secretary of state.
An FBI investigation said she was “extremely careless” but found her actions didn’t warrant criminal prosecution. However, Mr Christie and and the crowd disagreed as Mr Christie repeatedly yelled “guilty”.
He said she has “selfish, awful judgement” and was to blame for various foreign policy problems in Libya, Syria and elsewhere.