Group plans news conference for Tuesday.
Former rising GOP star had been found guilty of receiving gifts, money and loans from CEO of Virginia-based company.
Says venue should have taken extra precautions because events hosted by Brown had been violent in the past.
Authorities say 25-year-old shot them, then burned bodies.
Sim Ervin King, 21, arrested in connection with murder of 32-year-old man.
Aptly named vehicle helps with security detail.
Sen. Elizabeth Warren also speaks during event at Cincinnati Museum Center.
Mayor Paula Hicks-Hudson, police Chief George Kral and members of Blackman, Hopings families address media.
Millions of dollars at stake.
Aroldo Castillo-Serrano gets 15 years for actions at Marion egg farm operation.