Washington (CNN) Federal investigators exploring whether Donald Trump's campaign colluded with Russian spies have seized on Trump and his associates' financial ties to Russia as one of the most fertile avenues for moving their probe forward, according to people familiar with the investigation. The web of financial ties could offer a more concrete path toward potential prosecution than the broader and murkier questions of collusion in the 2016 campaign, these sources said. One year after the FBI opened an investigation, the probe is now managed by special counsel Robert Mueller. Sources described an investigation that has widened to focus on possible financial crimes, some unconnected to the 2016 elections, alongside the ongoing scrutiny of possible illegal coordination with Russian spy agencies and alleged attempts by President Donald Trump and others to obstruct the FBI investigation. Even investigative leads that have nothing to do with Russia but involve Trump associates are being referred to the special counsel to encourage subjects of the investigation to cooperate, according to two law enforcement sources.Sources described an investigation that has widened to focus on possible financial crimesThe increased financial focus hasn't gone unnoticed by President Donald Trump 
 Question:Trump has denied any collusion and maintains that his business empire has "no involvement with _" and that he has "no loans, no nothing" from Russia.
Russian