The family of slain Eskom employee Thembisile Yende, whose body was found 13 days after she disappeared, have been dealt another blow with the death of her brother.

Mboneni Yende, who was at the forefront of the investigation into Thembisile's disappearance before her body was discovered, died in hospital after an operation on Wednesday.

Thirty-year-old Thembisile was reported missing on May 17 2017. Her decomposing body was found in a store room next to her office in Pieterboth sub-station in Springs, on the East Rand.

Postmortem results revealed that she was strangled and hit on the head.

Thembisile joined the power utility in 2015 and had been working as a trainee technician. A family spokesperson said Mboneni had been diagnosed with gastritis [stomach discomfort] late last year.

"He died in hospital around midnight. He was admitted two weeks ago for an operation," said Brian Sithole.

"That sickness was painful. He could not even bend when he walked."

Sithole described Mboneni as a "selfless" person.

"He had a good heart. I've never met anyone who is as selfless as he was. Everything to him was about the other person.

He said Mboneni's death was a blow to the Yende family as they were still looking for those responsible for Thembisile's death.