A man drove over his estranged wife, fled the scene and then returned briefly to retrieve his license plate without helping his dying spouse, police said Friday.

The 51-year-old man struck his wife at a pedestrian crossing in the southwestern Swiss town of Nyon on Thursday evening, cantonal (state) police said.

He then drove off, only to come back in order to collect his front license plate, which had fallen off the car as a result of the accident, police said.

As passers-by tended to his badly injured wife the man left the scene again. He was subsequently arrested by a police patrol.

The wife, 49, died later in the hospital.

Police said the man, of Portuguese origin, appeared to have driven over his wife on purpose and a criminal investigation has been opened.