They came to Singapore from the same Pakistani village last month to sell tissue paper.
But an alleged falling out between the three men, presumably over earnings, ended with the death of one of them earlier this week.
His legless body was found stuffed in a suitcase at Syed Alwi Road on Wednesday.
Police officers arrested the two other Pakistanis, aged 43 and 25, at Rowell Road in Little India the next day.
A pair of human legs, severed at the thighs, were recovered that night at the Muslim Cemetery near the junction of Jalan Kubor and Rochor Canal Road. They are believed to belong to the dead man, who was 59 years old.
The three men were staying at a Rowell Road lodging house during their time here.
The owner of the lodging house, who declined to be named, told The New Paper yesterday that the older suspect and the victim checked in about a month ago, on May 17.
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He knew the older suspect as Mr Rashid and the victim as Mr Mohamed Noor. They shared a room and the younger suspect, whom he knew as Mr Rizwan, arrived 11 days later.
He was accompanied by three other Pakistanis - two women and a man.
The six Pakistanis were here on social visit passes, Chinese evening daily Shin Min Daily News reported.
According to the lodging house owner, they had flown in from Karachi and were supposed to fly home together on June 27.
Chinese evening daily Lianhe Wanbao reported that the three people who were part of the second group checked out around noon yesterday and left Singapore soon after.
On Wednesday around 9am, just hours before the body was discovered, Mr Rashid was spotted buying an electric saw from the nearby Mustafa Centre. A worker at the mall reportedly said he was calm when he did so.
He was just as composed around 9pm that day - about three hours after the body was found - when he paid his rent to the owner of the lodging house.
The owner told TNP that Mr Rashid even joked with him.
Following the gruesome discovery of the body in the suitcase, police officers went looking for the two men at the lodging house on Thursday.
TNP understands that both men were not there when the officers arrived. But they were ambushed and arrested when they turned up around 3pm.