One solution, twice attested in Roman Britain, was to bury a victim under the floor of a building. At Vindolanda, a young child was found buried in a barracks block in 2010. Previously, in 1930, two bodies (seemingly a man and a woman, although some dispute about the genders, sometimes described as two men) were found buried under a house near the Housesteads fort, one with a bit of a blade still stuck inside.

Another option was to dump the body down an abandoned well, which were commonly used as refuse dumps in ancient cities. There is a famous well in Athens known as the Agora baby well, mostly because it is full of infant remains, and seems to have been used by midwives to dispose of stillborn infants. But some of the remains in the well were adults , and seem to have been murder victims; Maria Liston, the forensic pathologist at the American School, has identified up to 17 potential murder victims (although a few may be hastily disposed war deaths after Athens was sacked by the Heruli).

https://bonesdontlie.wordpress.com/2012/03/30/murder-in-the-agora-aia-talk-by-maria-liston/

Hi there - we're happy to approve your question related to your creative project, and we are happy for people to answer. However, we should warn you that many flairs have become reluctant to answer questions for aspiring novelists and the like, based on past experience: some people working on creative projects have a tendency to try to pump historians for trivia while ignoring the bigger points they were making, while others have a tendency to argue with historians when the historical reality does not line up with what's needed for a particular scene or characterization. Please respect the answers of people who have generously given you their time, even if it's not always what you want to hear.

Additionally, as amazing as our flair panel is, we should also point out that /r/AskHistorians is not a professional historical consultation service. If you're asking a question here because you need vital research for a future commercial product such as a historical novel, you may be better off engaging a historical consultant at a fair hourly rate to answer these questions for you. We don't know what the going rate for consultancy work would be in your locality, but it may be worth looking into that if you have in-depth or highly plot-reliant questions for this project. Some /r/AskHistorians flairs could be receptive to working as a consultant in this way. However, if you wish for a flair here to do this work for you, you will need to organize this with them yourselves.

For more general advice about doing research to inform a creative project, please check out our Monday Methods post on the subject.