A South Korean-born man who was adopted by an American couple at the age of three is set to be deported and separated from his wife and children - because his parents did not apply for US citizenship for him.

Dean Crapser arrived in the US 37 years ago, but now faces being sent to a country he knows little about.

His plight has been branded 'wrong and inhumane', after he was confined in an immigration detention center for the past nine months.

Dean Crapser, pictured with wife Anh and daughters Christal, one, and Christina, five, is being deported to South Korea, the country he left at the age of three

Crapser, 40, who lived in Washington with his family, was told by a judge that he must return to Korea, leaving behind wife Anh Nguyen and three children, who are US citizens.

He said he was physically abused by his adopted parents, having been separated in the care system from his older sister.

Dae Joong Yoon, executive director of the National Korean American Service & Education Consortium, said: 'It's heartbreaking news. I'm sure he doesn't have any idea what he can do in Korea.'

Without knowing the language and the culture, it will be so difficult to survive Becky Belcore

Lori Walls, from the Washington Immigration Defense Group, told NBC: 'Adam and his family are heartbroken at the outcome.

'He was eligible for a discretionary form of relief called "cancellation of removal", and the immigration judge decided he did not deserve this relief.'

She said Crapser had waived an appeal because he is desperate to get out of detention.

Becky Belcore, who was adopted at the age of one and brought to the United States from South Korea, said she was with Crapser in the courtroom.

She said: 'He has been in detention for almost nine months. He's been separated from his children. It is really hard for him.'

And she said it was 'wrong and inhumane' to send Crapser back to South Korea.

'Without knowing the language and the culture, it will be so difficult to survive,' she said.

Crapser in the family's Washington home with daughter Christal, aged one

Belcore said the immigration center seems worse than jail because visitors are not allowed to touch or hug detainees, and must talk on a telephone.

Belcore added that Judge John C. O'Dell appeared very matter-of-fact when he told Crapser he will be deported.

Seven years after he and his older sister were adopted, Crapser's first US parents abandoned them, and the siblings were separated in the care system.

He moved between foster and group homes before moving in with Thomas and Dolly Crapser.

In 1991, the couple was arrested on charges of physical child abuse, sexual abuse and rape. They denied the charges.

It's heartbreaking news. I'm sure he doesn't have any idea what he can do in Korea Dae Joong Yoon

Thomas Crapser's sentence included 90 days in jail, and Dolly Crasper's included three years of probation.

Adam Crapser got into trouble with the law after he broke into his parents' home. He claimed he was trying to retrieve the Korean Bible and rubber shoes that came with him from the orphanage.

He was later in more trouble for stealing cars and assaulting a roommate.

Federal immigration officials say they became aware of Crapser after he applied for a green card. His criminal convictions made him deportable.

The National Korean American Service & Education Consortium says an estimated 35,000 intercountry adoptees do not have US citizenship, and has called for legislation to address this.