Investigators in Oregon believe they know who’s responsible for a wildfire that’s burned nearly 30 square miles, forced hundreds to flee their homes and by early Wednesday showed no signs of being contained.

The chief suspects: a group of teenagers who giggled and recorded video Saturday afternoon while lobbing fireworks into a parched canyon.

Warm summer temperatures and nearly nonexistent rain have dried out vegetation and turned the Beaver State’s forests into tinderboxes. Officials warned that the threat of wildfire was high and urged caution as Oregonians descended on the state’s parks and forests over the holiday weekend.

One of the visitors was Liz FitzGerald, who told the Oregonian that she was hiking in the Columbia River Gorge 70 miles east of Portland when she saw a teenage boy hurl a smoke bomb into Eagle Creek Canyon.

Another boy recorded the incident with his cellphone, and some girls in the group giggled as the incendiary exploded in the trees below, sending up what FitzGerald thought was smoke from the fireworks.

“I was probably 4 feet away from him. I said, ‘Do you realize how dangerous this is?’” FitzGerald recounted to the newspaper. ” ‘This place is so dry.’ ”

A short time later, she encountered hikers who’d also seen the teens setting off fireworks. The hikers were walking to the trailhead to notify park officials about the teens’ dangerous behavior.

FitzGerald decided to run back to the start of the trail to do the same thing, the newspaper said. By then, she could see flames and smoke. It was obvious that it was a forest fire. And it was growing.

As she ran, she encountered the teens again. She said they seemed oblivious to the ramifications of their actions.

“My adrenaline is through the roof,” FitzGerald said. “I said, ‘Do you realize you just started a forest fire?’ And the kid who had been filming with his cellphone said, ‘But what are we supposed to do about it now?’ And I said, ‘Call the fricking fire department!’ ”

Investigators have said the fire’s cause was “misuse of fireworks.” The teen with the firebombs was a 15-year-old male from Vancouver, Wash. They found him in the trail’s parking lot and interviewed him. No one has been arrested and no formal charges have been made. Authorities have not released the teen’s name. Video surfaced on YouTube of police interviewing the teens near the entrance to Interstate 84 after what FitzGerald described as a brief minivan chase.

As investigators build their case, they urged anyone with information about the fire’s start to contact authorities, particularly “anyone who heard fireworks or other explosions in the area of the Eagle Creek Trail/ Punch Bowl Falls on Saturday between 10am to 5pm.”

Eagle Fire Update – We need your help! We have identified the suspect in this devastating fire as a fifteen year old…

Posted by Oregon State Police on Tuesday, September 5, 2017

People spewed venom at the offenders on an Oregon State Police Facebook post that sought information.

“How does it feel to know you personally destroyed so many people’s lives and livelihoods,” one woman wrote. “All the trees and animals you’ve destroyed and history. You deserve a Darwin Award. You probably are the most hated person in the region right now. Good job.”

Meanwhile, authorities are trying to contain the fire and contend with its effects. For people in the Portland area, that meant ash falling from the sky in a manner eerily reminiscent of the eruptions of Mount St. Helens in 1980, according to the Willamette Week.

As it grows, the fire has disrupted some lives and endangered others.

It stranded 150 hikers on Saturday, who were unable to leave the trail because of the blaze, according to the Associated Press. Authorities airdropped supplies to them before they were rescued on Sunday morning. Some 400 homes in Warrendale and Dodson were evacuated because of the flames. I-84 was closed for 27 miles for everyone except people trying to flee.

The fires near Portland are reminiscent of another major fire started by juveniles that killed people and engulfed tourist towns in Tennessee last year.

Two juveniles were charged with arson after the “Chimney Tops 2” fire tore through the eastern part of the state, damaging 2,400 properties, injuring 150 and leaving 14 dead, according to The Washington Post’s J. Freedom du Lac, Sarah Larimer and Lindsey Bever.

Investigators have not released the age or gender of the youths, saying Tennessee law shields the identities of juvenile offenders. The charges were ultimately dropped, according to Gatlinburg ABC-affiliate WATE, because prosecutors said they were unable to prove criminal responsibility beyond a reasonable doubt.

But many of the people affected said the youths should be tried as adults because of the monumental loss.

“There were so many lives lost in this fire, due to this fire, and due to them being inconsiderate,” said Katerina Milles, a 45-year-old who had been staying in a shelter. “There were so many lives lost. Animals’ lives lost. Humans’ lives lost. And the beautiful place that we lived in, you know, that was — ”

Then she sighed, and said: “You know. It’s not good. I mean, it’s not good.”

Read more:

People thought this iconic Oregon rock formation fell on its own. Then a video emerged.

They met on a dating site and went bowling. It was a setup, police say, and now he’s dead.

This couple didn’t tip their Latina server. They left a hateful message instead.