So much has been invested by so many in the cover-up of Vincent Foster’s death that you have to wonder whether the full truth will ever be known.

But a key witness in the case, harassed when he refused to change his testimony to the FBI regarding what he saw in Fort Marcy Park the day the White House deputy counsel’s body was found, is expanding his lawsuit against the U.S. government in an attempt to unravel the mystery.

Patrick Knowlton has already filed suit against the FBI and others for harassment and federal witness tampering for what he claims is a pattern of systematic intimidation designed to get him to change his story.

His attorney, John Clarke, is about to name a new defendant in that suit — Scott Jeffrey Bickett, a top-clearance Pentagon employee who reportedly free-lances for the FBI. According to a new book, “The Secret Life of Bill Clinton,” by Ambrose Evans-Pritchard of the London Sunday Telegraph, Bickett has admitted to vandalizing Knowlton’s car the night before he was to be interviewed by the FBI for the second time on May 11, 1994.

Bickett reportedly followed Knowlton for several blocks and parked his car behind Knowlton’s near the Vietnam Memorial. Shortly after Knowlton left, Bickett took a tire iron and smashed the headlights and radiator of Knowlton’s car. But a retired police captain, Rufus Peckham, witnessed the vandalism and reported the incident, along with Bickett’s license plate number, to the U.S. Park Police.

The car Bickett was driving that day belonged to his brother-in-law, Ronald Huston. The U.S. Attorney’s Office questioned Bickett, who, according to Evans-Pritchard, admitted vandalizing the car. But the Justice Department refused to take any further action. The British reporter also discovered Bickett’s employment status and relationship with the FBI by examining the federal intelligence data bank.

According to Evans-Pritchard, Bickett’s security clearance is listed as “Active SCI,” which stands for “sensitive compartmented information.”

“What we have here is a crime, a confession and no prosecution,” says Knowlton. “It’s amazing.”

Clark promises that Bickett won’t be the last name added to his growing lawsuit. Knowlton’s life has been turned upside-down since July 20, 1993, when he unwittingly turned into the parking lot of Fort Marcy Park.

He saw two other cars in the lot, an unoccupied 1983 or 1984 rust-brown four-door Honda with Arkansas license plates, and a metallic blue-gray four-door sedan parked three or four spaces away, occupied by a man who stared menacingly at him. Neither car was Foster’s.

When Knowlton got out of his car, the other man got out of his automobile. Knowlton walked down a footpath to a wooded area to relieve himself, while the other man got back into his car. About 90 minutes later, Foster’s body was found 700 feet from the parking lot. The man and the car were still there a few minutes later when Knowlton returned to his car and drove away. Interestingly, Foster’s car was not there.

The next day, when Knowlton learned Foster’s body had been found in the park, he reported what he had seen to the U.S. Park Police. The FBI interviewed him nine months later. In October 1995, Evans-Pritchard interviewed Knowlton for a story in the Telegraph. Only then did Knowlton learn that his statement to the FBI had been falsified. In particular, Knowlton was shocked to read in the official report that he could not identify the suspicious man in the park.

As a result of the Telegraph story, on Oct. 26, 1995, Independent Counsel Kenneth Starr subpoenaed on Knowlton to testify before the Whitewater grand jury. For a week leading up to his testimony, Knowlton reports a campaign of sustained harassment by at least 28 people including two FBI agents. It was witnessed by at least three other people including Evans-Pritchard and investigative reporter Christopher Ruddy.

That harassment was the basis for his civil rights suit.

Starr’s prosecutors were never interested in what Knowlton had to say, only in discrediting him before the grand jury or in getting him to change his testimony to conform to the FBI report.

If officials aren’t forced to reconcile the dozens of contradictions and inconsistencies in their official reports on the death of Foster, perhaps someone will be held accountable for the harassment of Patrick Knowlton.

Note: Read our discussion guidelines before commenting.