ELMWOOD PARK, N.J. — Three months ago, Rosalia Juskin dialed 911 from behind a locked basement door. She said her husband, Michael, 100, was ignoring her pleas, so she asked the police for help opening the door. When they arrived, Ms. Juskin, 88, described the episode as an accident.

It was the third time in three years that the police had been called to the couple’s home at 58 Spruce Street. Not seeing any obvious threat, they left, and then notified adult protective services. “He’s 100 years old, and she chalked it up to that,” the Elmwood Park police chief, Michael Foligno, said. “She didn’t feel it was purposeful.”

On Sunday, Mr. Juskin killed his wife with an ax in her bed as she slept. Then he took a knife into the bathroom and killed himself by cutting his wrists, said John L. Molinelli, the Bergen County prosecutor. A relative found the couple’s bloodied bodies the next day.

The crime tore asunder a relationship that had been unraveling in recent years, pulled at again and again by the erratic and occasionally aggressive behavior of a man who showed signs of mental deterioration, the authorities said. Those who heard the cries for help said they either understood the tumult as a symptom of old age, or lacked the resources to intervene.