Nigeria's chief justice, Walter Onnoghen, was absent on Monday from the first day of his fiercely-disputed trial overshadowed by the country's upcoming elections.Onnoghen had been scheduled to attend the Code of Conduct Tribunal, a special court set up to enforce ethical conduct among holders of public office.Last week he was accused of breaching a transparency law that requires public officials to declare their assets. It also bars them from having bank accounts in foreign currencies.Lead defence attorney Wole Olanipekun, heading dozens of lawyers who had gathered in a protest against the case, said Onnoghen was absent as he had not been properly served with the summons. The court ordered an eight-day adjournment. However, a High Court ruling, in a separate development, raised doubt over the resumption.The allegations against Onnoghen have sparked criticism from opposition figures and civil society.They claim President Muhammadu Buhari's government is plotting to remove Onnoghen ahead of a likely close-fought presidential election on February 16. If the result is disputed, the Supreme Court, chaired by the chief justice, has final authority over determining the outcome.Buhari's main challenger, former vice-president Atiku Abubakar of the main opposition People's Democratic Party, said he viewed the unexpected charges against Onnoghen with "apprehension and suspicion".Buhari's administration, he charged in a press release, was "pressuring an independent and self-governing arm of government". "Any attempt to force Justice Walter Onnoghen to vacate his office, four weeks to an election for which the unpopular Buhari administration has shown every intention to manipulate, is a move pregnant with negative meaning," he added.Olanipekun led a huge defence team of more than 90 lawyers - a presence, he said, that aimed to "protest" at flawed charges and the court's competence to try Onnoghen.He said that the summons to appear in court had been received by Onnoghen's personal assistant, but under Nigerian criminal law, the defendant must be served personally with the document.The chairperson of the tribunal, Danladi Umar, adjourned to January 22 and ordered the summons to be served properly.Separately, however, the Federal High Court restrained the authorities from trying or prosecuting Onnoghen until its review of the case is heard on Thursday - a move that places a question mark over the adjourned case. Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.