This urban legend seems to be true. This case, surprisingly, has occurred several times, in 1994 in Miami, in 2003 in Kansas City or in 1999 in New Jersey, where guests, German tourists, complained about the nauseating smell that emanated from somewhere in the room In which they had spent all night. The hotel staff, trying to rectify the problem, found a dead man under the bed.
Source: https://supercurioso.com/3-leyendas-urbanas-resultaron-ciertas/