Oscar Pistorius is seeking solace in God and attends church regularly, his family said, as the athlete prepares for his return to court this week.

The Olympic and Paralympic athlete, who is accused of murdering his girlfriend, will return to Pretoria magistrates court at 9am on Tuesday. The hearing is expected to last 10 minutes, with the case likely to be postponed until August so that police can complete their investigation.

It will be Pistorius's first formal public appearance since he was released on bail in February following the fatal shooting of model Reeva Steenkamp in what he claims was an accident.

Lois Pistorius, the athlete's aunt, revealed he has been quietly attending church most Sundays. "He's been going to church and people from the church are visiting him," she said. "He attends the English service and I attend the Afrikaans service.

"At home he's reading the bible a lot. If you've got a purpose in life and you believe in God, it gives you a reason to understand things when they're not going smoothly because you rely on God who is everlasting and always there. Humans make mistakes. None of us is perfect."

Pistorius, 26, has been living as a virtual recluse with Lois and her husband, Arnold, at their luxury home in Pretoria. He has been photographed only once on an athletics track and seen once out with friends.

Lois, 55, added: "He rarely goes out. It's very difficult for him. He reads a lot of stuff, newspapers, the Bible, he's doing some work on the computer.

" He's got a strong character and he's exercising a lot. We brought in some equipment for him to exercise on. A family member or two and friends come and join him.

"It happened on 14 February. Where are we now? Three and a half months later. Things must go back to normal. We hope he will compete again one day because he's got the natural talent."

Pistorius sometimes fails to shave, Lois added, though she did not know if his beard will be seen in court. "He's got one then he hasn't got one. It comes and goes."

She said Pistorius's finances have taken a hit from legal fees and the loss of commercial deals. "He has lost a lot of sponsors but there will always be bread on the table. Someone will help you somewhere. What do you need in life? You don't need a fancy car or fancy house to survive," she added.

Pictures of the bloody bathroom where Pistorius shot Steenkamp were broadcast by Britain's Sky News last week. Lois said she had not yet talked to Pistorius about the images of what she described as "the accident scene". She added: "It was leaked by police officers. My opinion is not important.

"The most important thing is that he must get a fair trial and the truth must prevail so people can understand it was terrible accident and tragedy. They were two beautiful young people and this has changed their lives together."

One of the pictures showed the toilet where Steenkamp was killed, with a trail of blood from the room, a panel missing from the door and two police markers indicating bullet holes. Pistorius's lawyers have demanded an explanation from the police as to how the photos emerged.

Pistorius has admitted to shooting four times through the locked door but says he was acting in self-defence against what he thought was an intruder. His trial is expected to start later this year.

The eNews Channel Africa reported that prosecutors have drawn up a list of 27 potential witnesses including rugby player Francois Hougaard – a friend of Pistorius rumoured to have briefly dated Steenkamp – and Pistorius's ex-girlfriend Samantha Taylor who accused him of being unfaithful.

In an interview on the Carte Blanche programme on South Africa's M-Net channel, Arnold Pistorius said his nephew had received counselling and was going to the gym twice a day "to get his mind right".

Arnold added: "I saw him crying this morning before he went to the gym. We did the standard procedure, he reads scripture and he prays. He grieves all the time and, it's such a personal thing, it's difficult for me to talk about this but he's going through a very, very tough time."

Pistorius still has photos of Steenkamp on his walls, his uncle said. "He grieves every day. He's getting his pastor in once a week from his church. At the house they have a gathering every week and they work on this, but it's tough."