A tragic story is getting even more complicated: A fourth suspect was arrested Monday in the murder of a Florida couple who had 16 children, many of whom had special needs and were adopted. Police say at least six people were involved in the crime and that there were "other motives" than just robbery. Surveillance video from the couple's home shows five people wearing masks and dressed in black entering the house from two entrances. Nine of the children were in the home when the murders took place, and one escaped to a neighbor's house to seek help. The men were only at the home for 10 minutes, according to the tapes, and the crime was "very well-planned and methodical," according to police.