SINGAPORE - Armed with a video camera, he spent two hours on his day off staking out Block 83 at Commonwealth Close, where he lives.
His target: An inconsiderate neighbour above his unit who had been dumping food out of her kitchen window.
Mr Ken Kee's efforts to catch the neighbour red-handed paid off a Saturday afternoon two weeks ago when he shot a short video clip and took some photographs of a woman dumping spoonfuls of food from her eighth-storey kitchen window.
The 14-second clip, which has been making the rounds on Facebook and on citizen journalism website Stomp, shows her scooping what looks like porridge out of a claypot and throwing it out of the kitchen window.
Mr Kee, who works in the oil and gas industry, told The New Paper that the problem started last June, when his family's washing got mysterious spots and splatters while being hung to dry.
The Kees live in a third-storey unit.
Initially, the 42-year-old and his wife brushed it off as bad luck.
Months later, the problem worsened, with the incidents escalating to up to three times a week, forcing them to dry their washing indoors instead.
"This inconsiderate act is unforgivable and selfish. My wife and I have been tolerating this nuisance for many months," Mr Kee said, showing The New Paper pictures of these clothes.
"All our clothes have been stained, even my kids' school uniforms. Some of the stains could not be washed off and the clothes had to be thrown away.
"We don't leave our windows wide open any more because we want to save ourselves the trouble of having to clean up the mess."
The frustrated couple started their own "detective work", which included placing a mirror outside their kitchen window to observe where the litter was coming from.