Washington - Former secretary of state Colin Powell counselled Hillary Clinton on how best to keep official emails out of public view, according to a leading Democratic lawmaker and close ally of the White House candidate.Emails made public by US lawmaker Elijah Cummings - top Democrat on the House of Representatives' Oversight Committee and a long time Clinton supporter - appear to corroborate what Clinton has told the FBI about Powell's advice to her during its investigation into her emails.Powell preceded Clinton - now the Democratic party's presidential nominee - in the office of top US diplomat. He served under Republican president George W Bush from 2001 to 2005. Powell emailed Clinton advice on the use of digital devices in 2009, just two days after the start of her tenure as secretary of state. "If it is public that you have a BlackBerry," he wrote, "it may become an official record and subject to the law"."Be very careful," Powell warned her. "I got around it all by not saying much and not using systems that captured the data," Powell said.The retired four-star general revealed one particularly useful trick: "I had an ancient version of a PDA (personal digital assistant) and used it," he wrote.BlueprintCummings, in a statement accompanying Wednesday's email release, said that the correspondence showed Powell gave Clinton "a detailed blueprint on how to skirt security rules and bypass requirements to preserve federal records, although Secretary Clinton has made clear that she did not rely on this advice". Prior to the release of the emails by Cummings, Powell denied having schooled Clinton in email detection avoidance."The truth is she was using it [her personal email] for a year before I sent her a memo telling her what I did," Powell told the New York Post newspaper last month. "Her people have been trying to pin it on me," he told the tabloid.Republicans on the House Oversight Committee led a months-long probe into Clinton's email practices following revelations that she had used a private email server for official business while secretary of state.Cummings faulted House Republicans for their relentless pursuit of Clinton over the email issue, calling it wasteful and excessive."The Republican obsession with Secretary Clinton has reached a fever pitch, and they have been using taxpayer resources to single her out in a desperate and abusive attempt to hurt her presidential campaign," he said.FBI Director James Comey concluded that Clinton had been "extremely careless" in her use of a private server, but declined to press criminal charges against her. Republicans are pushing for additional investigations into Clinton's private email server, hoping it will thwart her bid in the November 8 election to succeed Democratic President Barack Obama in the White House.