A former federal prosecutor involved in the early prosecution of a January 6 defendant was arrested in the stabbing of a driver on a Florida highway after a crash last week, authorities say, and new video shows a confrontation with a Good Samaritan who tried to intervene.

Tampa resident Ahmed Gahaf said the incident unfolded after he stopped to help an incapacitated driver who appeared to be experiencing a medical episode on the I-275 southbound on September 26.

When the driver woke up, he accelerated forward, hit Gahaf's car and while attempting to drive around Gahaf's car, he collided with a second car, according to the Florida Highway Patrol.

Patrick Scruggs, a 39-year-old former federal prosecutor, was inside the second car that was hit, according to highway patrol. Gahaf told CNN that Scruggs stopped, got out of his car and went up to the vehicle that had hit him.

Scruggs then shattered the driver's side window and attacked the driver inside with a folding knife, leaving "multiple stabs and cuts in the arm," according to a Florida Highway Patrol arrest report.

Video taken by a witness and released by highway patrol shows Gahaf on the phone with a 911 operator and trying to stop Scruggs. The video appears to show Scruggs making a swipe at Gahaf with his knife, which nearly hit him in the chest, Gahaf said.

"I'm thinking he's coming to help, you know, he's coming to help, but he comes in like he already has plans," Gahaf told CNN Sunday. "I came in close to him to try to tell him stop... and he came in close to me, like one foot away from me, from my chest with the knife. And he said 'you too? You want to kill me?' I backed from him and was still with 911 and he kept going to stab him (the driver)."

Scruggs is now facing felony charges of armed burglary, aggravated assault and aggravated battery with a deadly weapon, according to an arrest affidavit.

John Nohlgren, Scruggs' attorney, noted his client's career as a federal prosecutor in an email to CNN. He urges the public to "keep an open mind" saying his client has no prior criminal history.

"This was a chaotic situation involving multiple crashes caused by only one person on one of our area's busiest bridges. That person was not Mr. Scruggs. There is much more to this incident than what is being reported and we are diligently working to bring to light the full facts of what occurred," wrote Nohlgren.

Gahaf said he was shocked when he learned the knife-wielding man he confronted was a former federal prosecutor.

"I cannot believe it, you know, that's what drive(s) me crazy. He knows the law," he said.

Jail records show Scruggs was released 10 hours after he was first booked at the Pinellas County Jail on a $65,000 bond.

Scruggs spent a decade at the Middle District of Florida's US attorney's office in Tampa as senior litigation counsel, according to his LinkedIn profile. This summer he joined a private law firm in Atlanta.

He was involved in the early prosecution of January 6 defendant Adam Johnson, known as "lectern guy," for making off with Speaker of the House Nancy Pelosi's lectern.

Barnes & Thornburg told CNN in an email that Scruggs is no longer employed at its law firm.