Angola's former first son Jose Filomeno dos Santos has spent hours contemplating the marble floor and wood-panelled walls of Luanda's Supreme Court where he has been on trial since December.The 42-year-old child of Jose Eduardo dos Santos could soon hear whether he is guilty of stealing millions of dollars from Angola's sovereign wealth fund, which he oversaw from 2013 to 2018.His father is so far not under investigation, but prosecutors are closing in on the dos Santos children.Jose is the first dos Santos member to stand trial since President Joao Lourenco launched a purge of Dos Santos' administration in a bid to tackle graft soon after he took over in 2017. Isabel dos Santos, the ex-president's billionaire daughter, was this year charged with financial crimes related to her tenure at state oil company Sonangol - from which she was removed after Lourenco came to power.READ | Angola ex-president defends son over embezzlement chargeAged 77, and believed to be in Spain for medical treatment, Jose Eduardo Dos Santos has barely reacted to the prosecution of his children."Touching dos Santos would be very politically risky," said Paula Cristina Roque, an Oxford University-based Angola analyst.ALSO READ | Isabel dos Santos plans legal action against media over 'Luanda Leaks'She believes Lourenco - known as "JLo" amongst Angolans - strategically targeted the ex-ruler's offspring because they had no strong backing in the ruling People's Movement for the Liberation of Angola (MPLA)."Dos Santos is a different story." 'No facts'Critics of Lourenco's anti-corruption drive say the high-profile cases barely scratch the surface. They say other suspects -- including former vice-president and Lourenco protege Manuel Vicente -- are shielded from investigation.The MPLA is set to elect a new party leader next year and Lourenco is being careful not to make the wrong enemies, analysts say.Targeting the unpopular dos Santos children is also seen as a strategy to rack up support ahead of general elections in 2022.From her luxury exile in London and Dubai, Isabel dos Santos decried the investigations as a "witch-hunt". But at the offices of Angola's Palace of Justice, overlooking the oceanside capital Luanda, prosecutors disagree.MUST READ | Portuguese hacker says he is behind Angola corruption leaks"There is a focus on these two children because... prosecutors found that they mismanaged public assets," said attorney general spokesman Alvaro Joao. He told AFP several politicians were also under investigation, including former transport minister Augusto Tomas, who was jailed for corruption last year."At the moment there are no facts to suggest the ex-president has committed any infraction," Joao said.He said as a former head of state, dos Santos would also be immune from criminal prosecution for five years after the end of his mandate. Corruption legacyDos Santos took office after the death of Angola's first president Agostinho Neto in 1979.He remained in power for 38 years, during which he saw the former Portuguese colony through a 27-year civil war that ended in 2002.Peace was followed by an economic boom as investors rushed in to tap Angola's vast oil reserves.Dos Santos reserved top jobs in his administration for close friends and family.READ | Pompeo hails Angola's anti-graft campaignNatural resource wealth amassed in the hands of a few, and evidence suggests large sums of public money were diverted to offshore accounts."Corruption is an evil that has corroded Angolan society since the (MPLA) regime was implemented," said lawyer Salvador dos Santos, who heads an anti-graft association."At the highest level no one lived off their salaries or through legal means," he said. "It was all about scam and fraud."He said the investigations commanded by the new government had raised awareness and prompted Angolans to speak out.'His time will come'As evening traffic crawled along Luanda's Hoji Ya Henda avenue, passers-by did not hold back their disapproval of the dos Santos family."I don't even have words for Isabel dos Santos," said mechanic Tayson Madrugada, 20. "She messed around with our country and opened businesses that did not give jobs to the youth."Driver Jacob Denis, 48, said only dos Santos senior was responsible for handing powerful posts to his children.READ | Angola's Dos Santos says she is 'ready to fight' against 'untrue' graft claims"The kids are not to blame," said Denis. "When you are a son and your father gives, are you not going to take?"Angolan investigative journalist Rafael Marques de Morais was confident dos Santos would be held accountable once his immunity is lifted in 2022."Many of the people who have been indicted refer back to him," Marques told AFP. "There are investigations... and he will have to answer questions."Judges at his son's trial last week received a written response from dos Santos stating he had personally authorised former central bank governor Valter Filipe da Silva to move $500m to Switzerland to guarantee an investment fund.Da Silva is accused of embezzling the money alongside dos Santos's son and two others. Both denied that."His time will come," Marques said of the former president. "The question is whether his health will hold him steady until 2022."