A woman has been accused of having sex with an 11-year-old boy who played lacrosse with her son.

Su Hyon Dillon, 44, was arrested and charged with four counts of first-degree child rape last Wednesday in Puyallup, Washington.

Police say the sexual abuse occurred between May 2014 and May 2015 when Dillon's husband was coaching the Emerald Ridge Lacrosse Club and she was known as the 'team mom'.

According to a probable cause affidavit, the child didn't speak of the sexual encounters for years, but became emotionally disturbed and suicidal, cutting himself and frequently missing school.

Su Hyon Dillon, 44, was arrested and charged with four counts of first-degree child rape last Wednesday in Puyallup, Washington

The child's mother sent him to live with his father in Virginia in an effort to help his mental state.

While in Virginia, the child came forward and disclosed the sexual abuse during a counselling session.

Police back in Washington opened an investigation on April 5 when the child's mother contacted them with the allegations.

The boy told investigators that things started when Dillon kissed him on the lips when he was 10-years-old at her house, where he said he would spend time often with his friends on the team.

'He said the kiss was on the lips when he was 10', according to the court documents reported by KIRO-TV.

'He said one time on a ride home she pulled over and told him that what they were doing was a secret because she wanted their relationship to continue and become more serious', and that 'the first time they had sex he was spending the night at her house'.

Dillon was freed without bond. She has pleaded not guilty

Police interrogated Dillon, who at first denied having sexual relationship with the boy, according to the documents.

As the interrogation went on, Dillon admitted to having sex with the child, but blamed him, saying that he had initiated the sexual contact, according to police.

Investigators dismissed that defense, saying that an 11-year-old boy cannot consent to sex, and that the culpability lies with the adult.

Dillon confessed that she 'was the adult and should have known better,' the documents said.

She also admitted to 'having problems in her marriage and that the victim made her feel good.'

Dillon was released without bail from Pierce County Jail but cannot return home, as she has minor children and is banned from all contact with juveniles as a condition of bond.

She could not be reached for comment and is next due in court on May 14. She has pleaded not guilty.