LAS VEGAS (AP) — Newly released Nevada state trooper dash cam and motorist videos of the moments before the fatal shooting of a 20-year-old man by U.S. Bureau of Land Management officers will be helpful in a federal wrongful death lawsuit related to the slaying, an attorney representing the dead man's family said Tuesday.

Testimony also revealed during a public airing of evidence Monday that D'Andre Berghardt Jr. twice shrugged off stun gun darts and was hit in the head with a baton before he was shot and killed when he got into the trooper's cruiser on a state highway near Red Rock Canyon National Conservation Area.

"We're going to obtain accountability for the Berghardt family. I'm confident of that," said attorney Jacob Hafter, who represents Berghardt's mother, Tracy Meadows.

Hafter alleges the federal officers were undertrained, overzealous and enraged that Berghardt didn't follow their instructions. The federal lawsuit seeks unspecified monetary damages for Meadows and a declaration that the Bureau of Land Management rangers used excessive force and violated Berghardt's civil rights.

Bureau officials usually don't comment about cases with lawsuits pending. Agency spokesman Christopher Rose declined Tuesday to comment on Hafter's allegations.

A Las Vegas police detective who investigated the Feb. 14, 2014, shooting told a hearing officer Monday that the officers who fired feared that Berghardt was reaching for a police assault weapon or could begin driving the idling vehicle, KLAS-TV in Las Vegas reported (http://bit.ly/18itIbe ).

A camera in the Nevada Highway Patrol vehicle shows what authorities said was Berghardt's hand on the AR-15 in a gun rack, and the dash cam video shows a Bureau of Land Managemen agent approaching with his handgun drawn seconds before gunfire is heard.

Thirteen shots were fired, and Berghardt was struck seven times, according to testimony. Bullets broke his ribs, pelvis and an arm. The Clark County coroner ruled the shooting a homicide, although the finding does not establish fault.

Earlier, the Nevada state trooper, Lucas Schwarzrock, a five-year department veteran, is seen running to aid the two Bureau of Land Management rangers struggling with Berghardt. Schwarzrock didn't fire his weapon.

In the federal lawsuit, Hafter has identified the officers as Ranger Meagen Martin and Agent Brian Loftin. Meagen has 18 years of law enforcement experience; Loftin, 10 years, Rose said.

The lawsuit claims the officers could have gotten medical help for Berghardt when they found him disoriented and walking with a backpack, bedroll and rolling suitcase on a paved shoulder of the highway about 20 miles west of downtown Las Vegas. Bureau of Land Management officials have said Berghardt was walking in traffic and annoying passing bicyclists.

Family members said Berghardt rode a bus from Los Angeles the day before, but failed to meet a relative in Las Vegas.

Clark County District Attorney Steve Wolfson has issued a preliminary finding that the Bureau of Land Management officers were justified in the shooting. According to policy, no findings or conclusions were made as a result of Monday's hearing. A final order will be made in coming weeks.

Prosecutor Michael Staudaher, the chief deputy district attorney who presented evidence on Monday, declined Tuesday to comment.

The three new video segments augmented witness cellphone video posted online shortly after the slaying.

It showed two officers physically preventing Berghardt from entering two vehicles stopped in traffic as the highway patrol officer arrives with his dash cam rolling.