A woman has been arrested in connection with the murder of her mother-in-law who died after being attacked with a chopper.

A 64-year-old man called Police at about 7.30pm to report that his 84-year-old mother was seriously injured and had collapsed in his home at 116 Belcher's Street in Western.

He said he had found her upon his return home after work.

Police found his mother lying unconscious in the sitting room with many chop wounds. She was sent to Queen Mary Hospital but was certified dead at 7.51 pm.

The man also told Police his 58-year-old wife was missing.

Police found the woman wandering inside a supermarket at 51 Smithfield Road. She was arrested in connection with the case.

Western District Crime Squad is investigating.