SINGAPORE - A 78-year-old man slotted a pinhole camera under a toilet door to film his daughter's maid showering on four occasions over three days.

The Singaporean was jailed for six months on Thursday (Feb 3) after he pleaded guilty to a voyeurism charge.

The retiree was a teacher for more than 30 years until the late nineties, his lawyer S. S. Dhillon told the court.

There is a gag order to protect the identity of the victim.

Deputy Public Prosecutor Yohanes Ng said in court documents that the maid was showering in a common toilet at around 3.40pm on March 10 last year when she saw a pinhole camera with a cable slotted under the door about 10cm into the toilet area.

She quickly turned off the water and got dressed. When she came out of the toilet, she saw the offender praying in his bedroom.

When the man was confronted later, he denied any wrongdoing. But he later admitted to his daughter that he had inserted a camera under the toilet door while the maid was showering.

The victim, along with her employer and the offender, went to a neighbourhood police centre the same day to lodge a report.

Investigations revealed that from March 8 to 10, the man had operated a borescope to intentionally observe the victim showering in the toilet on four occasions without her consent.

A borescope is an optical instrument designed to assist visual inspection of narrow and hard-to-reach areas. The device, which the offender claimed to have bought one to two months earlier, was seized on March 11.

"In her statement, the victim stated that she felt offended and sad as a result of finding out about the accused's actions because she treated him like her own father, but he betrayed her trust." said DPP Ng.

In his written sentencing submissions, the prosecutor asked for a prison sentence of eight to 10 months, citing the need to strongly deter would-be voyeurs, especially from committing such offences against vulnerable victims such as their domestic helpers.

In mitigation, Mr Dhillon said the culpability of his client was at the lower end and the harm caused was in the low to moderate range.

This was because there was only a single victim, the offences were committed over a short period, and there was no evidence the man had viewed or circulated the videos.

He also said that his client was of frail health and had no prior criminal record.

In meting out the sentence, District Judge Lim Wen Juin said the culpability and harm cannot be considered low, but he noted that the offence was an aberration given the man's age and absence of a criminal record.

For voyeurism, the offender could have been jailed for up to two years and fined. The sentence could also have been doubled as the victim is a domestic worker.