advice needed

Hi there was a fir register under420 and120ipc there were 4-5 accused in the case out of that only 1has participated in the investigation and there is no proof founded against that person and all other have been declared po by the police but not yet by the court now the accused who participated in the inquiry is filling for quashing of fir as inspite there were no proof against the person is whole investigation even then charge sheet was filled only against that person so what should be done now