An elderly man in Shanghai is suspected of killing his wife and their grandson over the weekend while suffering a bout of depression, Shanghai's Metro Express reported on Tuesday.

On Saturday evening, the woman in her 60s and the 7-year-old boy were found strangled to death by friends who had come to pick them up to attend a wedding ceremony.

The man allegedly tried to kill himself by jumping into a river when he realized he had caused the deaths, the newspaper cited neighbors as saying.

Neighbors also said the boy, a first-grader in primary school, lived with his grandparents after his parents divorced.

On Saturday afternoon, the woman and the boy were seen together traveling home, neighbors said.

Police are investigating.