HAPPIER DAYS: Jordan Case with his infant nephew in 2004.

Give a 20-year-old enough magic mushrooms to make 30 people trip hard. Then put him up against three cops armed with Tasers, beanbag guns and Glocks.

It’s a recipe for disaster, and that’s exactly what happened 18 months ago when Jordan Case wandered into a stranger’s apartment, freaked out and was fatally shot by police in Tualatin.

Before he died on Oct. 22, 2006, the unarmed aspiring physicist was Tasered 12 times, hit with nine beanbag rounds and shot four times. In a federal lawsuit to be filed April 3, Case’s parents claim their son’s death was totally unnecessary.

“It didn’t need to happen that way,” says his father, Laird Case, breaking down in tears during an interview with WW. A Salem deputy fire marshal who graduated from the state police academy, he sees it as a classic case of cops relying on weapons over brains.

The lawsuit, to be filed by lawyer Steven Sherlag, seeks unspecified damages from Washington County, the cities of Tualatin and Sherwood, and the three officers in the shooting. Family members say they also want additional training for police on crisis intervention.

The Washington County district attorney’s office in November 2006 cleared Sheriff’s Deputy Glenn Howard, Tualatin Police Officer John Jayne and Sherwood Police Officer Adam Keesee of wrongdoing. None of the three responded to WW’s requests by phone for comment.

In interviews with police investigators obtained by WW, the three say they were terrified by Case, who showed almost superhuman strength and endurance.

“My level of fear is skyrocketing, ’cause he’s not responding to anything,” Howard recalled. “You don’t understand what that feels like until you actually fear for your life.”

A former cross-country champ at Reynolds High School in east Multnomah County with no criminal record, Jordan Case had been accepted to Oregon State University in fall 2007. He was living in Tualatin and working for $15 an hour in a warehouse to save for tuition.

Police who searched his apartment after the shooting found marijuana plants, mushrooms and instructions for making mescaline. One of Case’s friends, William Bradley, told police Case was “a self-proclaimed veteran of psychedelic drugs.”

Case’s body tested positive for psilocybin, the active ingredient in psychedelic mushrooms. Bradley told police Case had about four ounces of shrooms in his apartment and had planned to eat them all on the night he was killed. Jordan Ruiz, another friend, said Case believed four ounces would be enough to give him a “mind trip.” That’s more than 30 times the typical dose of one-eighth of an ounce for a strong trip.

On the night Case was killed, Sally Arellano, a 29-year-old single mom, awoke on her couch to find Case standing over her in shorts and a T-shirt, waving his hands over her body as if trying to feel her energy. She ordered the barefoot stranger to leave her Tualatin apartment.

Arellano later told police she thinks Case came in through an unlocked door. Case told Arellano he was on mushrooms, started to leave, apologized, threw a pillow at her, tried to rub her pants, apologized again, then lay down on the carpet.

Arellano called 911, telling the dispatcher Case was on mushrooms. But according to the lawsuit, the police were never told that fact.

Arellano ran to her 8-year-old daughter’s bedroom. Case forced the door open, and they struggled, with the daughter joining in the fight. When Officer Jayne arrived, Arellano had Case, who weighed 128 pounds, pinned face-down on the floor.

Arellano fled and Jayne began his own stand-off with Case, who alternated between sitting calmly on a bed and lunging at the officer. At one point, Case touched a light on the ceiling and froze, saying “I’m right here.”

“There’s something about his eyes,” Jayne recalled. “Just real wide and, like, piercing, I guess.”

Jayne backed out of the apartment and Case followed, leaping a fence in a single bound (a feat Jayne called “impressive”). Case ran across the road and then circled back but ignored repeated orders to lie down. Once he briefly pulled down his shorts as if to urinate.

Backup officers arrived and pummeled Case with beanbags and Tasers. Officer Keesee told investigators he assumed Case was on PCP or some other drug. “He’s standing up in the middle of a Taser cycle, which was beyond me,” Keesee said. “I’ve heard it’s possible, but seeing it was just unbelievable.”

Case tried to open the door of a police cruiser that had a rifle inside, locked to a console. Howard fired three bullets into Case, but he still struggled to enter the car. “I remember thinking, unplug him, unplug him, we’re fucking done with this shit,” Howard recalled. He fired a fatal fourth shot to the back of Case’s head.

Sherlag says each of the cops weighed over 200 pounds and could have subdued Case. Instead, he says, they dealt with a confused subject by shouting commands and firing weapons.

“They should have called an ambulance, not the cops,” Sherlag says. “It was a totally avoidable tragedy.”