In a statement, the PJ explains that the woman is suspected of having "planned the victim's death in advance, administering a substance of drugs in this food, in toxic and lethal amounts".
"In addition, the detainee subtracted high sums of money that belonged to the victim," the press release add.
The facts occurred in July 2018 inside the residence where they both lived, in Lisbon.
"The Judiciary Police carried out multiple steps aimed at locating and detecting the suspect, who currently is using another identity and had completely changes her appearance, so as not to be recognised," the note added.