Two days after a murder charge was dismissed against a Minnesota state trooper in the shooting death of Ricky Cobb II, the slain motorist's family says they plan to petition the U.S. Department of Justice to investigate the Minnesota State Patrol for both the shooting and the department's overall training.

Speaking with Cobb's family in a news conference Tuesday at the Hennepin County Government Center, attorney Bakari Sellers criticized the State Patrol for alleged shortfalls laid out by the prosecution in a recent report. "I don't think there's any more glaring example of a department that needs to be investigated than the Minnesota State Patrol," he said.

Hennepin County Attorney Mary Moriarty charged trooper Ryan Londregan with murder and manslaughter in January for the fatal shooting of Cobb, 33, during a traffic stop on Interstate 94 last summer, as Cobb shifted his car into drive and it lurched forward. On Sunday, Moriarty announced she was dismissing the murder charge and additional claims made against Londregan, citing an expert's analysis of video from the scene and recent statements by Londregan's defense attorney.

Londregan's attorney Chris Madel on Tuesday said Sellers' request for a federal investigation is "the last gasp of a dying case."

In a nine-page report by Washington-based law firm Steptoe LLP, which contracted with Moriarty's office, prosecutors recommended dismissing charges. The report indicated that evidence would "likely show support" for the defense theory that Londregan believed Cobb was reaching for the trooper's gun and that he needed to shoot Cobb to protect himself and his partner.

Sellers attributed some of his criticism of the State Patrol to the prosecutors' report, which also found fault with the tactics Londregan and fellow trooper Brett Seide used as they tried to remove Cobb from his vehicle and arrest him for violating a domestic no-contact order. A use-of-force expert is quoted in the report as saying the two troopers' tactics were "horribly executed."

The report, dated June 2, faults Londregan for unlocking Cobb's passenger side door and opening it while the car was running and as his partner was instructing Cobb to exit the vehicle. The prosecutors wrote that opening the door was a "tactical blunder" and said it appeared to surprise Cobb and "led him to reflexively shift the car into drive, causing it to lurch forward."

The report suggests that the troopers should have considered letting Cobb go and arresting him later because they knew his address. While the report says the troopers should have considered these other options, it also alleges that State Patrol training does not cover or warn against removing a driver from a car while it's running.

On Monday, Madel brushed off the notion that troopers should have let Cobb go and insisted that Londregan acted heroically to save his partner's life.

State Patrol Col. Christina Bogojevic defended the agency. "I stand by the intensive training provided by the State Patrol and fully support our troopers who work hard every day to keep Minnesota safe," she said.

The DOJ declined to comment for this story. Sellers said the request to investigate will be made to the Civil Rights Division of the Department of Justice and the Federal Bureau of Investigation.

"One of the things that I won't do and his family won't do is allow Ricky's legacy to be in vain," Sellers said.