As seen in the camera footage, a woman was walking with her daughter in Thong Nhat Ward of Bien Hoa Town in Dong Nai, neighboring Ho Chi Minh City, last Sunday night when a man approached them on a motorbike.
He stopped the bike but kept the engine running and chased after the mother, who was using a smartphone while walking.
He then took out a knife and tried to stab her while grabbing for the phone.
The girl was stunned for a moment but very quickly, she rushed in and did her best to rescue her mother.
Neighbors heard the mother and daughter screaming for help and came to their rescue.
The footage then showed two men in the neighborhood chasing after the robber and seizing his motorbike.
After two days of searching, police arrested Nguyen Quang Vinh, 26.
Vinh had just been released from jail last year for robbery.