Two Auckland teenagers were violently and sexually assaulted while taking a train home on the weekend.
The mother of one of the victims has voiced her concerns on social media to try to track down the attackers.
Jen de Montalk said her 15-year-old daughter and male friend were travelling home on the train on Saturday about 5.30pm, when they were confronted by five drunk men wearing Four Square costumes and masks.
"The kids were on the train near them and one of the men started walking around and telling my daughter to put her hand in his pouch, because he was wearing an apron.
"He then got his dick out and exposed himself to her," she said.
"Then one of the other guys suddenly took a disliking to the boy she was with. He called him a faggot, rolled up his sleeves and started choking him."
De Montalk said her daughter began yelling for help while her friend fought off the attacker, but nobody came to the teenagers' aid.
"People were filming it but nobody stepped up to help, and the Auckland Transport staff didn't intervene."
She said the man headbutted the teenage boy, and a stray punch clipped her daughter in the side of the face.
"The man then stole the boy's phone so my daughter went to a train security guy and basically had to convince him and beg him to come and help.
"They somehow got the phone back and the men were kicked off the train, but quite a lot of time had passed before anything was done about it."
De Montalk said did not know about the attack until three days later, and suspects the teenagers were too scared to let anyone know because "they thought they might get in trouble or wouldn't be allowed to use the train again".
She said she was "extremely shocked and upset" when she found out.
"I am absolutely gobsmacked that people would stand by and let five grown men attack two skinny 15-year-olds and not intervene.
"This should never have happened. Everybody should be able to pay a fare and use public transport and be guaranteed they will have a safe journey.
"Now I don't know whether I can let my daughter on public transport any more."
De Montalk said her daughter spoke to police on Tuesday and they visited her friend at school yesterday.
"I want the men to be held to account. You can't sexually expose yourself to a child and you can't attack a child physically. You just can't carry on like that.
"They for some reason had decided my daughter's friend was gay and decided to attack him. He is not gay, he is just a skinny kid, but their motivation was homophobia."
The teenagers were given filmed footage of the attack by a passenger on the train.
De Montalk said she decided to post the video on social media in case someone recognised the offenders.
"If anyone knows anyone fitting that description I'd love to hear from you. The police are involved and I want to make sure we get these degenerates," her post read.
"This was a serious assault on a pair of 15-year-olds, fuelled by alcohol. Shame on Auckland Transport and shame on those who sat by and did nothing."
Police inquiries into the assault are continuing.