It shall be lawful for the county board of any county, by an order to be entered upon its records, to fix upon a sum not exceeding $1,000 as a reward to be paid to any person who shall hereafter pursue and apprehend, beyond the limits of the county where the offense shall have been committed, any person guilty of any felony or other high crime, which reward shall be paid by the county where the offense was committed, on the conviction of the criminal: Provided, nevertheless, that said reward shall not disqualify the person entitled thereto from being a witness.