SINGAPORE - An unemployed man wanted to get his older sister in trouble with the law by lying to the police, claiming that they had an incestuous sexual encounter when he was a teenager.

This was because the 26-year-old man was unhappy as his sister "had been trying to cause trouble at home".

Due to this false allegation, the 28-year-old nurse was investigated for incest and interviewed four times at Ang Mo Kio Police Division between March 31 and Sept 26 last year.

The man, who cannot be named due to a gag order to protect his sister's identity, was jailed for two weeks on Thursday (Jan 4) after pleading guilty to two counts of giving false information to the police. Two other charges for similar offences were considered during sentencing.

The man and his sister live in a Yishun flat. His fiancee, 28, started living with them last February before his parents told her to leave on March 25 last year.

At around 4am six days later, the man and his fiancee went to Sembawang Neighbourhood Police Centre to lodge a report. He lied to a duty officer, claiming that his sister had threatened them with a knife as she was unhappy that his fiancee had returned to the unit to collect her belongings.

Deputy Public Prosecutor Claire Poh said investigations later revealed that he had given false information. The accused also admitted afterwards that he had lodged the report because his sister objected to his relationship with his fiancee.

About four hours after he made the report, his fiancee phoned the police, saying that there was another dispute at the flat.

Officers arrived at the scene and told all parties to keep the peace before going down to the void deck with the couple. The fiancee then told one of the officers that the man had told her that he had sexual intercourse with his sister when he was about 16 years old.

The man told a similar lie when police interviewed him. Following this interview, officers started investigating the nurse for incest. A woman convicted of incest can be jailed for up to five years.

DPP Poh said: "The defendant had given this false information against the victim so that the police would investigate these allegations, thereby inconveniencing the victim."

The man finally admitted on Oct 19 last year that he had been telling lies.

Defence lawyer Michael Chang, who was assigned to the case under the Criminal Legal Aid Scheme, pleaded for his client to be jailed for a week.

He said the man has a mild intellectual disability and had been exempted from national service. The case involving his fiancee is still pending.

For each count of giving false information to a police officer, the man could have been jailed for up to a year and fined up to $5,000.