On November 30, Soochoon molested his final victim.
The woman told the Herald she was "disturbed" and "shaken" by the impromptu attack on a busy road in broad daylight.
But when she told her husband, who was in a car around the corner, they decided to track the man down.
They found him a few blocks away and after taking a photo on her phone, the victim drove to Auckland Central police station, where staff were able to locate Soochoon via CCTV and track him until he was arrested.
The woman rejected any suggestions her actions were heroic and instead chose to praise the police for their quick work.
She hoped the defendant got the help he needed while in prison.
Soochoon's first sex attack took place in October when he grabbed a woman's bottom as he walked past her on Grafton Bridge.
The following month, he committed five more indecent assaults within six days - three of which happened just half an hour apart.
Soochoon molested a woman who was also walking over Grafton Bridge early on the morning of November 27.
She broke away from him and screamed loudly but he pursued her.
"You've got a really nice arse. I love that arse," he shouted after her.
A short time later, he committed an almost identical attack on Queen St, before returning to the bridge and groping a third woman.
He fled when she screamed and the victim followed at a distance, while taking photos of him on her phone.
Soochoon was able to evade police but three days later, his luck ran out when he attacked the sixth woman.
When spoken to by police, Soochoon's explanation was simple.
"You said you acted on your urges because you felt like it," Judge Ronayne said.
The 33-year-old attempted to explain himself in court but the judge said he only sought to blame his actions on drug and alcohol abuse.
"Your apology expressed today carries no particular weight whatsoever," he said.
The court heard that Soochoon had served prison terms in 2012 for a slew of property and violence offences and in 2008 for an aggravated robbery.