suburbans....possibly plain clothes detectives?...who were the 3 members of the family? children? husband and wife and a child? maybe something involving the law, witness protection maybe? husband is a journalist...could be he came across something he shouldn't have or has information about exposing someone who's corrupt...how big was the box? they could have come back to get a computer for evidence.
hmmmmmmmmm now you've got me curious lol keep us posted!