Mr Marshall said the formal complaint was dealt with and nothing further could be done.
"There were three other young ladies who had made a tentative approach to police but then decided not to make any formal complaint. We want them to come forward and make a complaint."
Earlier in the day, Police Minister Anne Tolley took the "unprecedented" step of referring the Roast Busters issue to the Independent Police Conduct Authority herself.
That followed calls by Labour's police spokeswoman, Jacinda Ardern, for the IPCA to investigate police handling of the case.
In Parliament, Ms Ardern asked whether police questions about the complainant's clothing would imply that what the girl was wearing could influence the case.
But Mrs Tolley warned against "jumping to conclusions".
"The police have very strict protocols around the investigation of sexual assault charges and allegations. It is my expectation that police will adhere to those."
Prime Minister John Key said the handling of the Roast Busters case was "frankly, not good enough".
"This is a very serious issue. Parents around New Zealand will want to know that in the event their daughters make a complaint to police it's taken seriously, and actually, we're entitled to know all of the facts up front."
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What the police said this week and how their story changed:
Sunday
• Detective Inspector Bruce Scott tells 3 News: "None of the girls have been brave enough to make formal statements to us so we can take that to a prosecution stage ... We've told them [the boys] their behaviour is verging on criminal, if not criminal, and suggested it cease."
Monday
Statement is released at 12.41pm by Waitemata district communications manager Beth Bates. Highlights include:
• A full and thorough investigation has been conducted, but in the absence of significant evidence, such as formal statements, there is not enough evidence to prosecute the alleged offenders.
• Detectives have been working on the investigation since 2011 when a teenage girl came forward to police to informally report what had happened to her.
Second statement is released at 5.30pm quoting Mr Scott:
• Two males involved with Roast Busters interviewed by police that afternoon.
Mr Scott goes on to tell 3 News the reason police have not prosecuted anybody is they don't have sufficient evidence at this stage. Investigators' "hands are tied" until victims agree to make a formal statement.
Tuesday
Statement released at 1.32pm quoting Waitemata district commander Superintendent Bill Searle:
• Strongly rejects any suggestion that the inquiry was affected by the involvement of a police officer's son.
Wednesday
• At a 3pm interview in his office, Mr Searle tells the Herald a small number of victims have been identified. But avoids saying how many complaints have been received.
• 3 News at 6pm: A teenage girl alleges she was raped by the Roast Busters when she was 13. She told her family and they took her to the police to lay complaint. No charges were ever laid.
• Statement released at 7.17pm: Mr Searle confirms a complaint was received in December 2011.
Yesterday
• Statement released at 8.32am by Ms Bates clarifying total number of complaints: Four girls have been identified as victims, and one has made a formal complaint. Three of the girls were in contact with police in 2011. Another girl began discussions with police late last year. Of the four girls, one has gone through the process of making her complaint formal.