Nicola McDonough, 23, and her mother Margaret, 52, were found at the Premier Inn in Greenock, Inverclyde, at around 7am on Friday May 10 last year.
Margaret, who was discovered in a bedroom, died first while her social work student daughter, who was found in the hotel hallway, died three days later in hospital, where she had been in a critical condition.
Police Scotland said that a 31-year-old woman has been arrested in connection with alleged fraud, alleged culpable and reckless conduct and alleged attempt to defeat the ends of justice.
She is expected to appear at Paisley Sheriff Court on Monday.
A Crown Office spokesman said: "The Procurator Fiscal has received a report concerning a 31-year-old woman, in connection with alleged incidents occurring between May 2012 and May 2013.
"The report remains under the consideration of the Procurator Fiscal."