The father of Reeva Steenkamp, the model murdered by Oscar Pistorius, will give evidence for the first time next week to ask for the athlete to be given a lengthy prison sentence.
Barry Steenkamp, a former racehorse trainer, suffered a series of strokes following his daughter's death and did not attend Pistorius' trial on his doctor's advice.
While his wife, June, sat through testimony about how their daughter screamed as she was gunned down, he opted to watch on television.
But next week, as Pistorius is sentenced for an upgraded murder conviction, Steenkamp is expected to take to the witness box as the "final ace" up the prosecution's sleeve.
"He decided he had to say thank you to all the people that supported him but also to say goodbye to his daughter," a source told the Sunday Telegraph.
"He is very fragile but he wants to do it. If he can, it will be very powerful and emotional testimony."
The Paralympian killed Reeva Steenkamp in the early hours of St Valentine's Day 2013 by shooting her through a lavatory door. He claimed he believed she was a burglar and the original trial judge believed him, finding him guilty of manslaughter.
The athlete spent 12 months behind bars before being freed on parole in October last year. Since then, he has been on bail of just 10,000 rand ($930) and electronically tagged at his uncle's Pretoria mansion.
In December, South Africa's Supreme Court of Appeal overturned that judgment, ruling that Pistorius was guilty of murder and should return to prison.
Tomorrow, the original trial judge, Thokozile Masipa, will hear pre-sentencing arguments at Pretoria High Court. Murder carries a mandatory life sentence with a minimum of 15 years.