Video clips of Mr Yu in red underwear entering the sub-tenant's room were posted on citizen journalism website Stomp.
He was also said to have gone into the room multiple times a day - once when he was naked - and went through the tenant's belongings and took pictures.
Mr Yu told The New Paper he had gone into the room to check on the sub-tenant's electricity usage.
He said: "There was once I was just about to shower when I realised he wasn't in. So I went in to check on his electricity usage and took pictures with my phone.
There were also claims online that Mr Yu had entered a female tenant's room while she was taking a shower.
He claims that the former tenant has done all this to "take revenge on me (for) not returning his rental deposit".
He also claimed that the former tenant has pleaded guilty to four charges of mischief on April 10, and was convicted and fined $2,500.
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