Boyles
Anngela Boyle (L) and husband Colin Boyle (R) were sentenced to 30 years and 60 years in prison, respectively. Oakland County Sheriff's Office/Lake Orion Police Department

A woman has been jailed for 30 years after she recorded the child abuse of children aged just one to send to her sex offender husband in the "worst case" police had seen in decades.

A US District Court heard how Anngela Boyle, from White Lake Township, Michigan, had gone to extreme lengths to please her twice-convicted sex offender husband Colin Boyle.

Colin was jailed for 60 years the week before Anngela after pleading guilty to two federal counts of producing child pornography.

The twisted couple had previously admitted running a pornography scheme that involved taking nude photos and videos of four children ages ranging in age from one to nine, according to the Detroit Free Press.

According to court documents, the 27-year-old told police that she and her husband had together engaged a one-year-old girl and a three-year-old boy in sexually explicit activity on at least four occasions.

Police were shocked at the lengths she went to please her sick husband, one FBI agent wrote in an affidavit: "(The wife) explained to law enforcement that child pornography is the only thing that sexually excited Colin Matthew Boyle".

The couple were also convicted of criminal sexual conduct by the Oakland County Prosecutor's Office and both received a 25-to-60 year prison sentence in March this year.

Lake Orion Police Chief Jerry Narsh has said: "This type of investigation will always rock a community to its core, and the gravity of the crime and the helplessness of the victims impacts even seasoned investigators."

An FBI investigation into the couple began in 2015 after authorities found evidence that Colin had viewed child porn online and their home was subsequently raided.

Police found a camera at their address that contained a video of a nude one-year-old girl, whom the couple knew and a man's voice resembling Colin's was audible during the recording.

In the police interviews that followed the pair admitted sending each other child pornography over their cell phones.