Judge Huggett will likely deliver her judgment two weeks after.
The former rugby league player was jailed in 2022 for the January 1982 murder of his wife Lynette, with a judge finding he was motivated by a desire to pursue an unfettered relationship with a student.
They married two years later.
Dawson does not deny having sex with AB, but his lawyer Claire Wasley argued the alleged sexual activity began in 1981, after she had turned 17 and was no longer his student.
Earlier in the trial, AB said Dawson first became interested in her after he found a topless photo of her taken at a picnic when she was 15.
Detective Sergeant Laura Beacroft, who led Strike Force Southwood investigations into sexual abuse of students at northern beaches high schools, told the court on Thursday AB had not mentioned the photo when she was being interviewed by police in 2019.
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AB also did not tell police about another incident in which Dawson was allegedly “jostling” with other teachers to take her class in year 11, Det Sgt Beacroft said.
She also said the Department of Education did not uncover any records of complaints filed against Dawson while he was employed at Cromer High School between 1979 and 1983.
Neither Dawson nor his twin brother Paul, who the court heard kissed and cuddled with schoolgirls in a pool, have given evidence in the trial.
Support is available from the National Sexual Assault, Domestic Family Violence Counselling Service at 1800RESPECT (1800 737 732).
National Sexual Abuse and Redress Support Service is available on 1800 211 028.