Don't know what to think

My boyfriend and I have been together for almost three years. He has lied to me a handful of times and he confessed that he lied to me I didn't have to find out myself. So today I get a call from someone who has found his phone in the second floor bathroom of an abandoned hotel room that the building is scheduled for demolition soon. The hotel the phone was found at is attached to his work (he works at a restaurant). However the time that the guy said that he found the phone at was when he should have been just starting his shift. When I asked him about it he said that he had long boarded to work and he changed in the bathroom and it must have fallen out of his pocket.. Only thing is that the bathroom that he was saying that he changed in is on the first floor not the second. Anyone have any thoughts on this? I don't have a reason not to trust him but the whole thing seems so fishy.