Steven Karu's been at it again.

Over the years he has committed indecent acts around Palmerston North, including outside a Broadway Ave bakery and on a bus.

But on July 12, the 43-year-old got himself into trouble in Bulls.

Shortly before 10pm he was outside the town's medical centre on High St.

Inside, cleaning, was a 39-year-old woman.

"As the victim was vacuuming in the doctor's offices, Karu has approached the front of the building and stood within 30 centimetres of a full length window," police prosecutor Sergeant Stu Oram told the Palmerston North District Court yesterday.

The window revealed Karu performing an indecent act.

Mr Oram said he made no attempt to "put his genitalia away".

The cleaner got a fright, but thought Karu was urinating, so she moved to another part of the building.

Karu followed her and when she reached the foyer, he resumed his indecency behind the glass front door.

He said his offending was the result of voices inside his head telling him what to do.

"He also stated he would plead not guilty to the charge so he would get [the cleaner's] details and deliver anger and pain to her," Mr Oram said.

This mirrored an incident last year when Karu masturbated on a bus and from prison sent a letter to the 13-year-old girl who witnessed the act.

"If my mum dies when I'm in here, so does yours and your dad," the letter said.

Judge Gerard Lynch remanded Karu in custody until sentencing next month on a charge of committing an indecent act.

- © Fairfax NZ News