South Klang district police chief ACP Shamsul Amar Ramli said the four included the woman’s husband, who was the main suspect in the case.
“We also seized a car, a machete and several mobile phones,” he was quoted as saying by The Star today.
Housewife R Komathi, 42, sustained slash wounds on the head and body.
The case has been classified as attempted murder under Section 307 of the Penal Code.
A two-minute and 14-second video clip of the incident has been making the rounds on social media.
Komathi’s 13-year-old daughter lodged a police report over the attack that same day after being informed by an aunt.
The video shows the woman being slashed repeatedly by a man, with a crowd watching without daring to interfere.
The man drags the woman into a car, with the help of an accomplice, before driving off.
Klang (South) police chief ACP Shamsul Amar Ramli later said the assailants sent the victim to a hospital outside the Klang Valley where she was warded in a stable condition.