Concerned friends have urged a missing mother to get in touch with police after she disappeared with her newborn baby and sex offender partner, who raped a neighbour while armed with garden shears in a horrific hostage scenario in 1989. 

Constance Marten, 35, is currently missing with her British partner Mark Gordon, 48, a registered sex offender who was jailed for 20 years in the US for a vicious sex attack in which he took a neighbour hostage aged just 14.

Tonight the horrific details of his victim's ordeal were revealed for the first time as friends of Ms Marten spoke out about their concerns for the new mother, who has been missing for 12 days.

Gordon's mother last night claimed her son is a 'good boy' and that he has secretly married the British aristocrat, saying she 'does not know what all this is about'. 

Gordon was born in Birmingham, West Midlands, but he, his mother and his half-siblings moved to the US when he was still a child in 1989.

In April of that year, aged just 14, Gordon armed himself with garden shears and a kitchen knife, then attacked his neighbour in a four-and-a-half-hour ordeal which saw him take her hostage and sexually assault her.

Two young children were sleeping in the room next door at the time of the attack, documents show. 

US court records describe how Gordon is said to have broken in through the woman's bathroom window, before finding a pair of her stockings which he used as a makeshift mask to cover his face.

Once he had encountered his victim, the documents state: 'The suspect ordered the victim back into the bedroom and while still armed, demanded that the victim undress.'

He is then said to sexually assaulted and raped the victim.

There were a total of six charges against Gordon relating to the April 29 attack: one count of armed kidnapping, four separate counts of armed sexual battery and one count of burglary with a deadly weapon. He was convicted on all charges.

The file described Gordon's actions once he had entered the house: 'The suspect placed a nylon stocking over his face to conceal his identity since he lived next door and was known by her.

'The suspect was armed with a kitchen knife as well as a pair of hedge clippers and after the victim came out of her bedroom to investigate the dogs barking, came across the suspect lurking just outside her bedroom door. 

'The victim was held for a period of approximately four-and-a-half hours against her will by the armed intruder.

'After miranda [being given the right to remain silent], the suspect admitted to the crime and gave a sworn, taped statement outlining the sequence of events as they occurred.

'It should be noted that during the commission of the crime, the victim's two small children were sleeping in their bedroom.'

Gordon was tried as an adult and sentenced to 20 years in jail after finally being arrested following six weeks spent on the run. 

While a fugitive from the first attack, Gordon committed another violent armed raid just weeks later.

On May 21, he broke into a man's house while he was sleeping, grabbed a kitchen knife and then battered the householder around the head with a heavy shovel when he awoke.

Court documents state that Gordon encountered the man, one of multiple occupants of the house, lying in bed when he suddenly awakened, memek bernanah 'at which time the defendant beat the victim about his head and body' with the shovel. 

He then fled empty-handed leaving the victim seriously injured.

Police finally caught up with Gordon a month later on June 13 when he confessed to both raids.