it's a bit confusing the way it was stated
it said blood drops were found in the hallway and they went in with luminol and found traces not visible to the naked eye in the bathroom
so that makes it sound like they found visible drops first and then other blood evidence not easily visible
ETA: wanted to add the link
Houston detectives found drops of blood in the hallway that led to the bathroom and on surfaces in the bathroom.
Investigators discovered evidence of more blood by using a "chemical reagent" that reacts to the presence of blood that may not be visible to the eye, such as when a person has attempted to clean it up, the documents state.
Vence allegedly told investigators "that there should be no blood in the home and that no one was recently bleeding."
Testing subsequently linked the blood sample to Maleah.
Maleah Davis: Man who was watching her likely to be charged with murder, court documents say - CNN