The family of a graphic artist slain in Minnesota's deadliest workplace shooting is suing the company, alleging its leaders should have known his co-worker was potentially dangerous and taken greater precautions when firing him.

Deborah Beneke filed the lawsuit as the trustee for the family of Jacob Beneke. Beneke, 34, of Maple Grove was one of six people shot and killed last fall at Accent Signage Systems by Andrew Engeldinger, 36, before he turned the gun on himself.

The lawsuit also names Engeldinger's estate as a co-defendant and alleges that the Minneapolis company was grossly negligent, citing the Sept. 27, 2012, shootings as "reasonably foreseeable based on Engeldinger's past incidents of employment misconduct and his known propensity for abuse and violence."

The lawsuit requests damages in excess of $50,000.

"In my 33 years as an attorney, this is the most tragic case I have ever been part of," the family's attorney, Phil Villaume, said during a news conference Friday.

Despite the lawsuit's claims, Engeldinger's court and employment records show no history of physical threats or violence before the shootings -- only repeated warnings for being late to work and being verbally abrasive with colleagues.

Villaume said that they have "reason to believe" that Engeldinger had threatened other employees and that Beneke feared for his safety on the day of the killings.

"There were people, we believe the evidence will show, that were in fear of their safety of this man," he said.

However, Villaume admitted there was no evidence that Engeldinger made any direct threats against or was violent with Beneke or any of his other co-workers.

Difficult to prove

Peter Riley, a personal injury lawyer for Schwebel Goetz & Sieben who is not involved in the case, said it's typically "extraordinarily difficult" to prove gross negligence against an employer.

"It takes a very, very high level of culpability, almost to the nature of an intentional act," he said. "I've been doing this for 36 years, and I cannot recall a case where the facts were found to satisfy the gross negligence standard."

However, he said Beneke's family does have a case against Engeldinger's estate, although it's unclear whether the assets are worth much.

Accent Signage spokeswoman Wendy Khabie declined to comment on the lawsuit, saying the company's attorney has not yet had a chance to review it. Engeldinger's father, Chuck Engeldinger, referred questions to the family's attorney, Julia O'Brien. She did not return a telephone message seeking comment.

Engeldinger's parents told the Star Tribune last fall that their son may have had schizophrenia, although they were unaware whether it was ever diagnosed. He spiraled into depression after high school and eventually became delusional, rejected medications and eventually cut off contact with his family.

After a 12-year career with Accent, Engeldinger was fired the afternoon of Sept. 27. Before the meeting he retrieved a gun from his car and returned to the building, where he shot and killed owner Reuven Rahamim and five others, including Beneke. Also killed were Ronald Edberg, Rami Cooks, Eric Rivers and Keith Basinski. John Souter was seriously wounded but survived.

Beneke left behind a wife, Iliyana, and a 6-year-old son. His family also includes his parents and a sister.

Suit: Security was needed

The lawsuit alleges "that a reasonable employer in Accent's position would have, among other things, provided adequate security on its premises, locked its doors, monitored Engeldinger and would have attempted to terminate Engeldinger in a safe manner."

Villaume said Friday that smaller companies that terminate employees have security guards on premises to escort fired employees off the property.

Asked whether he had ever fired a colleague, Villaume admitted that he had and that he had done so without security.

"I didn't feel I needed it," he said.

Pressed on what evidence showed that security would have been necessary when Engeldinger was fired, he said:

"We believe they knew he had problems with mental instability. It was generally known that he had mental illness problems."

However, he said there was no evidence yet to back the claim that the company knew or believed Engeldinger was mentally ill. According to the lawsuit, the company should have known he owned several firearms and routinely practiced at a firing range.

Villaume said Friday he believed the company was aware, but could not say how he knew that.

The suit claims that Beneke, who referred to Engeldinger as his "nemesis," was killed "as a result of personal animosity, wholly unrelated to employment at Accent."

Beneke allegedly knew the firing was going to occur that day and was asked to keep the information a secret.

On the day of the shootings, the lawsuit said, Beneke drove a different vehicle to work than he normally did and told his wife: "It's good I'll have the truck, because if he goes crazy, he won't recognize that I have a different car."

Abby Simons • 612-673-4921