MIAMI: Irfan Khan, a naturalised US citizen from Pakistan with a wife and two children, worked hard to realise the American dream after arriving in this country in 1994.

He held jobs in South Florida as a taxi driver, service technician and operated a limousine company. He was an avid cricket player.

Then he stepped up to a California computer industry job in 2011 that promised a good living.

A short time later, Khan was indicted along with his father and brother, both Muslim imams at Florida mosques, with conspiring to provide up to $50,000 to the Pakistani Taliban.

Khan spent 319 days in solitary confinement before federal prosecutors abruptly dropped all charges in June 2012.

“It was very, very hard,” Khan said of his days spent praying and reading in that lonely cell.

Later, a federal judge ordered the acquittal of Khan's brother for lack of evidence, although their elderly father, Hafiz Khan, was convicted at trial and sentenced to 25 years behind bars.

He's serving that time at a federal prison in North Carolina.

Now, Irfan Khan is suing the US government for malicious prosecution, accusing authorities of essentially manufacturing a non-existent case against him.

He is seeking potentially tens of millions of dollars in damages.

A Miami federal judge refused the US Justice Department's attempt to get the case dismissed, and it's headed for a June 2015 trial date.

There have been countless complaints about government overreach and collateral damage in the war on terrorism since the al Qaeda attacks of Sept 11, 2001.

Yet it's rare for the Justice Department to lose any criminal case, especially in the national security realm, and rarer still for an individual to successfully sue the government for a flawed prosecution.

Khan, 41, has a chance to accomplish both.

Now back to driving a taxi, Khan said it's been impossible for him to get a better-paying job because of the notoriety of the original charges, which pop up any time a prospective employee searches his name on the Internet.

He's had trouble opening bank accounts, leasing a car and getting a mortgage. His children, haunted by their father's arrest, now fear the police.

Friends and even family shun him, asking that he delete their phone numbers in fear that they too will be targeted for surveillance.

“Everywhere I look is a dead end for me,” Khan said. “I was unfairly targeted and I don't want this to happen to anybody ever again. I just want justice.“

The Miami US attorney's office and FBI declined comment, citing the ongoing litigation. In court filings, the Justice Department denies fabricating evidence or painting a misleading picture of Irfan Khan's role in the alleged plot.

Assistant US Attorney Carlos Raurell said there was ample evidence to bring his case to a grand jury, which did approve his indictment.

“The government denies it knowingly misrepresented evidence, either affirmatively or through omission, to the grand jury or to the court in the course of (Khan's) criminal action,” Raurell wrote in a recent filing.

The Miami US attorney's office has never provided a public explanation for dismissing the charges against Irfan Khan, let alone apologised for leaving him in solitary confinement, which is common for terror suspects.

Law enforcement, particularly when it involves national security, is broadly protected from lawsuits, so Khan's attorney Michael Hanna faces a tough burden: He must prove to a federal judge that investigators fabricated evidence or acted with an “intentional or reckless” disregard for the truth, and also that they acted with malice.

Like many FBI terrorism support cases, the investigation into the Khans rests largely on more than 1,000 intercepted telephone calls and several money wire transfers.

The vast majority of these calls involve the father, Hafiz Khan, discussing Pakistani Taliban attacks, including some that killed Americans, and railing against Pakistan's government, mostly in the Pashto and Urdu languages.

Before all the charges were dropped against Irfan Khan, prosecutors accused him of just four criminal acts:

Three wire transfers in 2008, totaling $2,950, to a man in Pakistan named Akbar Hussein. Prosecutors claimed Hussein was a well-known Taliban commander, but Irfan Khan's attorney said he is actually the uncle of Irfan Khan's wife and that the name is quite common. The money, according to Hanna, was sent for Mrs Khan to use while she stayed at her uncle's house during a 2008 visit. Irfan Khan wired the money using his own name.

A 2009 phone conversation between Hafiz and Irfan Khan in which the father “calls for” according to a US government translation an attack on Pakistan's government similar to a suicide bombing at a Marriott Hotel a year earlier in Islamabad. Hanna said Irfan Khan never responded on the call. “It appears Irfan was charged for listening to his 80-year-old father's rants,” Hanna said.

A 2009 wire transfer of $500 to Irfan Khan's sister in Pakistan, again using Irfan's own name. Prosecutors contend that the sister, Amina Khan, is a Taliban supporter and that she likely gave the money to the terror group. But there was no direct evidence to support that, Hanna said. Amina Khan was also charged in the US indictment but has remained out of reach in Pakistan.

Another 2009 phone conversation in which Hafiz Khan asks his son when he would send money to the “Sharia people” in Pakistan, which the government said was a reference to the Taliban. Again, there's no evidence that Irfan Khan said anything in response. Hafiz Khan called the Pakistani government “big pimps” on the call.

“These charges should never have been brought. Irfan is completely innocent. What happened here is absolutely outrageous,” Hanna said.

Seeking money damages is the best way to hold the government to account, he added. “The FBI is the gold standard. This is the checks and balances that allow them to maintain that gold standard,” Hanna said.

During the Khan criminal trial, US District Judge Robert Scola pressed prosecutors to explain why the charges were dropped against Irfan Khan, but got no clear answers.

But Scola was clear that the evidence was far too slender against Irfan Khan's brother, Izhar, when he granted a rare judgment of acquittal during the trial in January 2013.

Another federal judge, then-US District Judge Adalberto Jordan, raised questions about the strength of the government case as early as 2011, during Irfan Khan's bail hearing.

“Discussing incidents is very different than embracing them,” the judge said of some of the FBI's intercepted phone calls. “And the sins of the father can't always be visited on the son.”