No one could see the homemade bombs Matthew Michanowicz was carrying as he rode his bike in downtown Pittsburgh on May 31, 2020.

The city was a tinder box that afternoon. Six days earlier, a Minneapolis police officer murdered George Floyd, sparking protests around the country. The day before, one in Pittsburgh devolved into a riot. Dozens were arrested. City leaders imposed a curfew.

The next day, Michanowicz rode his bike to check out the aftermath. He wheeled himself to a plaza below a skyscraper in the heart of downtown, planted the backpack with the three bombs he’d made and left.

They never exploded, but prosecutors said they could have hurt or killed someone.

Police found the bombs the next morning, quickly homed in on Michanowicz as a suspect and arrested him, federal prosecutors said in court documents. He was indicted on charges of illegally possessing three destructive devices, to which he pleaded guilty in August. On Monday, facing a 10-year prison sentence, Michanowicz, 53, avoided more time behind bars, instead getting time served and three years’ probation. He has to serve the first six months under house arrest.

Prosecutors had asked U.S. District Judge Donetta Ambrose for a prison sentence between 2½ years and just over three years. Ambrose’s office did not immediately respond to a request for comment from The Washington Post on Monday’s sentencing.

Michanowicz’s lawyer, Ken Haber, told The Post in a phone interview that the judge might have considered his client’s recent mental health issues and personal struggles. Within a year of placing the bombs, Michanowicz lost his job as a successful medical salesman who worked with neurosurgeons. His father and a good friend died. He got divorced.

“I think the judge was somewhat convinced that he had a breakdown,” Haber said, adding that his client has stressed that he never meant for the devices to go off.

About 2:30 p.m. on May 30, 2020, a planned protest that would swell to more than 1,000 got started, according to the Pittsburgh Post-Gazette. Two hours into what had been a peaceful march, things quickly changed. Looters hit at least a dozen buildings. Rioters set two police cars on fire. Police repeatedly hit protesters with tear gas. Four officers were hospitalized and several others injured.

Police arrested more than 40 people. City officials set an 8:30 p.m. curfew to try to quell the riots.

“We believe that a lot of these individuals who are creating trouble are not from the city,” Wendell Hissrich, Pittsburgh’s public safety director, said at the time. “However, we have to take a strong response to ensure that the residents and visitors of the city remain safe over the next few days.”

The next day, Michanowicz, a Pittsburgh resident, rode his bike downtown to survey the damage and leave the bombs.

About 8 a.m. June 1, police went to an open area in a downtown plaza to check out a report of a suspicious bag and found a green military backpack near a bike rack under some trees, prosecutors wrote in court documents. Inside, they discovered canisters and got a whiff of a “foul odor,” prompting them to call in the bomb squad.

Inside the bag, police found three used pepper-spray canisters, which Michanowicz had repurposed and filled with gasoline. He’d stuck wicks inside and fixed them in place with foam insulation. Police described the bombs as “homemade Molotov cocktails.”

Private security for Two PNC Plaza, the skyscraper, told investigators there was security footage of someone carrying the bag. The video showed a man ride his bike to the bike rack, dismount, take a backpack off the handle bars and then stash it under the nearby trees.

Two days later, an officer spotted a man matching the description of the person from the video, at the spot where they’d found the bombs. Michanowicz was arrested and interviewed by police. During questioning, authorities say, he admitted he was the man in the video but repeatedly denied he’d been carrying a backpack.

Agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives raided Michanowicz’s home, where they found fuses and foam insulation spray similar to what had been used to make the bombs. They also discovered 10 camouflage backpacks like the one carrying the bombs.

Although prosecutor Jessica Smolar did not explain why Michanowicz planted the bombs, she outlined years of substance abuse that peaked in 2020. Michanowicz reported he started using heroin in 2018, according to court records. Although he claimed he hadn’t done so since February 2019, his ex-wife told authorities she’d found heroin bags and alcohol in his home before his arrest.

Right after Michanowicz was charged, then-U.S. Attorney Scott Brady denounced him as an agitator.

“Michanowicz brought a backpack full of homemade Molotov cocktails to downtown Pittsburgh,” Brady said. “He wasn’t there to protest; he was there to engage in violent attacks.”

Haber pushed back on Brady’s assertion.

“This is the product of someone who was a highly successful person who had a bit of a breakdown,” he said.