Two of the seven men, Im Tae Woon, 24, and Lee San Ha, 20, were detained on Friday.
Police said a dispute between Park Gun-huk and Min Kyung-man, two South Korean businessmen living in the Thao Dien neighborhood of District 2, sparked the surprising act of violence.
Park called his “friends” from South Korea to fly over to Ho Chi Minh City and take revenge on his rival.
The men bought six hammers and a bundle of plastic zip ties in a pre-dawn attack on Min Kyung-man’s house.
They tied up Min and other people in his house before hitting them with hammers. The victims’ screams alerted neighborhood security guards who called the police.
While Im and Lee were caught, others escaped with two cell phones, VND30 million ($1,293) and other valuable properties.
The people in Min’s house were rushed to a local hospital for treatment. One man, Park Jung-ji, whose relationship with Min has not been revealed, suffered internal bleeding and head injuries, Tuoi Tre newspaper reported.