Labour department spokesman Snuki Zikalala told SAPA news agency that their first task was to get Nelson Shisane's payslip to determine if he had been registered with the department so that his wife could receive the death benefits she was entitled to under labour law.
"Even if we only have his ID number we can check whether he has been registered so that the family can be helped," Zikalala said.
"Even if he was seasonal worker he should have been registered."
Farmer Mark Scott Crossley, 35 and his employees - Simon
Mathebula, 43, Richard Mathebula, 41, and Robert Mnisi, 34 - were arrested on Monday at the Engedi game farm near Hoedspruit, about 350km northeast of Johannesburg.
This was after police recovered the skull, pieces of leg and bloodied clothes of a man identified as 38-year-old Shisane, at another game farm.
On Tuesday, the four were remanded in custody for a week by Phalaborwa Magistrate's Court, police spokeswoman Ronel Otto said.
Zikalala said the investigation was made difficult by the fact that the four men were behind bars, having been denied bail.
Despite shock and outrage expressed by leading trade unions, the story only rated a brief mention in the inside pages of South African newspapers on Wednesday, except for a front-page item in the Sowetan, a daily with a predominantly black readership.
Police spokeswoman Otto declined to speculate on the motive for the alleged murder but added that Shisane had been fired from his job at the farm last year.
The Johannesburg-based newspaper The Star had earlier reported that Shisane, who was apparently branded as a "troublesome" worker, had earlier returned to the farm to collect his clothing.
"The farmer allegedly refused to hand over the clothes and other possessions and burnt them," the paper said.
It said Shisane had returned again a week ago to collect some pots but was never seen again.