Suspicious circumstances surrounding the deaths of three elderly residents and injuries of two others at a nursing care facility in Gifu Prefecture remained unclear Monday, with investigators saying they found bruises on one of the deceased and the two who suffered injuries.

Police have been working to determine whether the incidents, which occurred between the end of July and mid-August at the Soleil nursing care facility in Takayama, Gifu Prefecture, constitute criminal cases.

Bruises were found on the chest of an 87-year-old woman who died earlier this month after her lung was punctured by a broken rib. The woman, identified by her relatives as Sachiko Nakae, a resident of Takayama, took a bath on the morning of Aug. 12 with the support of facility staff, according to Soleil officials. At around 4:40 p.m. that day she became pale and was rushed to a hospital, where she died the following night.