Christine Banfield's Murder: Detective Thomas Gadell Breaks Down Morning of Crime

The morning Christine Banfield was murdered was even more chilling than many realized ... with a new documentary laying out what investigators say was a carefully planned plot from start to finish.

Detective Thomas Gadell breaks down the case in FOX Nation's "The Au Pair Affair: Murder in Suburbia" ... detailing the actions of Brendan Banfield, who was recently sentenced to life in prison after being convicted of the deaths of his wife, Christine, and a stranger, Joe Ryan.

According to investigators, Banfield orchestrated an elaborate BDMS-fueled scheme involving his family's au pair, Juliana Peres Magalhaes, whom prosecutors said he was romantically involved with.

Gadell explains how Banfield allegedly confirmed Joe's arrival by text, waited nearby at a McDonald's while Ryan headed to the home, then later returned and set the rest of the plan in motion.

Investigators say Banfield ultimately tried to stage the crime scene to make it appear Ryan had attacked Christine before being killed himself ... including transferring Christine's blood onto Ryan in an effort to sell the story.