Remember the malay guy who fell into the river just recently, according to my aunt, previously there are such cases too, not only one or two plenty, so now we could believe it's some dirty thing doing stuffs, or i myself believe it's is cause no one could find the reason why the guy could actually disappear when his friend jump down to rescue him right after he fell. Sometimes it's good to believe then to regret. At times, thing unbelievable things do happened in our life, is just that we haven't met it, and no one would ever one to meet it.