New York ( CNN ) -- The father of the convicted would-be suicide bomber who planned to detonate explosives in New York City subways was sentenced Friday to four and half years in prison on charges that he obstructed a terrorism investigation and intentionally misled authorities . A federal judge handed Mohammed Wali Zazi , the father of Najibullah Zazi , four years for obstruction of justice and six months on charges of visa fraud , prosecutors said . He had faced the prospect of up to 40 years behind bars . The elder Zazi was found guilty in July of destroying bomb-making materials and conspiring to obstruct the federal investigation into his son 's and co-conspirators ' planned attack on the city 's subway system . Zazi 's then-attorney , Justine Harris , had argued that his client was unaware that his son was planning to blow up subway stations with bombs planted in backpacks . Najibullah Zazi pleaded guilty to planning the attacks in February 2010 . But prosecutor Andrew Goldsmith said the elder Zazi knew exactly what he was doing as he misled investigators . The assistant U.S. attorney told jurors that the father tried to cover up his son 's tracks by destroying valuable evidence , lying to FBI agents about people he knew and tipping off other suspects . `` ( Zazi ) is not charged with being a terrorist , '' Goldsmith said . `` But he lied , and that is a crime . '' A relative , identified as Amanullah Zazi , has admitted to helping Najibullah get terror training in northwest Pakistan 's Waziristan region , part of a volatile tribal area on the Afghan border . He pleaded guilty to related charges and cooperated with the government . He also testified in Mohammed Wali Zazi 's trial that the elder Zazi told him FBI agents were looking for him and three other men and told him to destroy chemicals that might be part of any investigation . Najibullah Zazi told authorities that while at the terrorist training camp , he `` had discussions with al Qaeda about targets including the New York City subway system . '' Those attacks were planned for September 2009 , prosecutors said .
NEW : Mohammed Wali Zazi is sentenced to 4.5 years in prison . He was found guilty of obstructing investigation , misleading investigators . His son , Najibullah Zazi , pleaded guilty to planning the attacks in February 2010 .