Home of Beika's Grenier Meitantei Conan : Season 1 Episode 418

A small three-story house is put up for rent in the neighbourhood and the Detective Boys decide to pass by it on the way home from school. Haibara tricks the real estate agent into giving them a tour of the inside and Conan notices that he could see Mouri's detective agency from the third floor window. The next day, they discover the house has been sold to an old couple and Conan finds them suspicious.