Police have carried out a series of raids following the stabbing of a good samaritan at St Albans.

The 69-year-old victim suffered life-threatening injuries when he went to the aid of a woman who was being carjacked on Kerrison Avenue on Sunday afternoon.

The man remains in a serious condition in hospital.

Two youths, a 15-year-old Wyndham Vale boy and 16-year-old Tarneit boy, were arrested in raids in Melbourne’s west yesterday.

Two 19-year-old men arrested on Monday have been charged over the carjacking.

An investigation remains ongoing.