A UK student claims she checked her phone while having a coffee - only to see her landlord showing a prospective tenant around her own room.
Lauren Newton, 21, from Truro in Cornwall, says she set up a motion-activated security camera beside her bed as a precaution after a series of run-ins with the property owner.
But she was shocked when the CCTV caught her "friendly and polite" live-in landlord coming into her room without permission to show a woman around - despite allegedly claiming he didn't even have a key for the door, the Daily Mail reported.
The high-tech camera - which she bought online for about £30 - immediately sent an alert to her phone showing a live view from inside her room where she was horrified to see the stranger being shown around.
Lauren claims she then confronted the landlord and he tried to "lie his way out of it" - completely oblivious that he had been recorded entering the room at the six-bedroom house in Harrow, north west London.
The graphic design student told MailOnline: "We were sat down having a coffee and we got a motion alert and when we opened the camera in the app we could see him in our room with a possible tenant.
"When we opened the app I never expected to see him in the room. I just thought the camera would have been triggered by a loud noise or something and then he was stood there - it was horrible and there was nothing we could really do.
"We were disgusted to see this and brought the issue up with him where we gave him the opportunity to own up.
"He initially tried to lie his way out of it until we mentioned we had CCTV. We've since had an apology - and thankfully we've now moved out."
As Lauren watched the landlord showing the woman around her room she decided to confront him over the phone.
But she watched live as the property owner appeared to ignore her call and continue with the viewing.
In the shocking security camera footage the man, dressed in a white robe, can be seen showing a woman around the room.
He points to the bed before touching Lauren's cupboard and chair while chatting to the woman with his hand on his hip.
The pair then walk off camera before leaving the room a few moments later.
Lauren, who moved in to the property in April last year, said: "We left it until we got home and we went upstairs to the flat and asked to have a word with him.
"We told him we had reason to believe that somebody had been in our room that evening.
"He lied to us, he said 'we had a builder in the bathroom' and I questioned him and said 'did he go through our bedroom?' and he said 'no'.
"We then told him 'we know you've been in our room this evening, because we've got CCTV' then he admitted it and apologised.
"That annoyed me because I thought'"you're not admitting it are you, I've caught you'.
"We made him aware that we have it on video now and that it's trespass and invasion of privacy.
"He tried to defend himself - he said the tenant turned up and it was last minute and he was only in there for two minutes."
Lauren, who has since moved home to Cornwall, says the landlord had texted her just a few hours earlier asking for permission to do a viewing - but she had said no.
Despite her refusal, the student alleges that he went ahead anyway in breach of their tenancy contract.
She said: "That's our home, it's just a bedroom but it's our life upstairs and it's not very nice.
"I never expected that he was the type of person that would do that. He was always quite friendly and quite polite with us really.
She is now warning others to buy security cameras if they live in a shared property in a bid to keep their rooms secure.
Lauren initially bought the camera after allegedly rowing with her landlord's wife after denying access to the room with just 20 minutes notice.
She said: "I just think it's worth spending a little bit of money just to be sure, especially for people like students just like ourselves when you go home to visit family.
"With a live-in landlord they feel that that area is theirs even though there's a contract in place and you're paying a lot of money just for a bedroom.
"They think they've got more ownership and particularly with a live-in situation I feel like that's the case so I think it's nice to know what's going on and just have that security."