The bodies of two people — a father and his daughter — were discovered in their home in Moshav Nir Israel, near Ashkelon, on Friday morning by the man’s wife.

Police suspect that the father, a doctor in his 60s, euthanized the daughter, who was in her 30s and was terminally ill with cancer, and then committed suicide.

The daughter’s body was discovered in her bed. Authorities believe that the father injected her first with morphine and then with air bubbles, which caused her death. He then reportedly hanged himself in an attached garage.

A second possible scenario, reported Israel Radio, is that the woman died in her sleep and, when her body was discovered by her father, he subsequently killed himself.

The father may have left a note explaining his actions, according to Israel’s Channel 1. An investigation into the deaths is ongoing.