The 20-year-old, who now might have to delay his upcoming start of college, was just one of four bicyclists in Minneapolis targeted in a three-week spree by a male motorist seemingly intent on hurting random cyclists, police said.
The suspect is believed to possibly work in construction, as one victim noted seeing a yellow vest, police said. Cops believe he is driving a white SUV, possibly a Bronco or a pickup truck, with a topper on the back.
"When somebody maliciously hurts your child and had intent, it's the absolute worst feeling," Jensen's mother, Kristin Piper tells PEOPLE.
Her son, who suffered a broken jaw, dislocated cheekbone and five fractures in the bone under his eye after the Aug. 7 incident, will undergo a second surgery Thursday to repair the damage.
The series of attacks began July 20, when the assailant drove toward a bicyclist on the street and hurled a cement chunk at him, causing him to fall and break his collarbone, according to Minneapolis police.
Another cyclist was seriously injured on Aug. 4 when a man threw a concrete stone at him. He fell and was knocked unconscious, suffering "very serious injuries," Minneapolis police spokesman John Elder tells PEOPLE.
Then on Aug. 7, the same day Jensen was attacked, police say the man drove toward a woman in a car around 4 p.m. on a Minneapolis street and heaved a concrete chunk, which crashed through her windshield but didn't hurt her, Elder said.
About 20 minutes later, the man drove up to Jensen and another cyclist, launching chunks of concrete at them. The other cyclist was also hit but suffered only minor injuries, Elder said. Jensen was not wearing a bicycle helmet, his mother said, and there is no state law requiring one.
Attacks the Work of Lone 'Sick Individual'
Police are continuing to search for the perpetrator, whose motive is unknown, but Elder said, "we are under the belief that this is the work of one person."
Despite the rash of terrifying attacks, neither police nor bicycling advocates believe the assaults are part of a broader "us versus them" culture war with motorists in Minneapolis, a city known for being very bicycle friendly.
In fact, "relationships continue to improve" between the two groups, Ethan Fawley, executive director of the Minneapolis Bicycle Coalition, tells PEOPLE. "The narrative that there is extra conflict between people who drive and people who bicycle is very overstated."
Piper, calling the assault "senseless," said both she and Jensen, an avid cyclist who was riding his Fyxation fixed bike, agree. "It's a sick individual," she said. "I don't think there's anything brewing."
Cyclists and motorists peacefully co-exist for the most part, Elder said, though "at times there's angst between the two groups, but this is not common."
Jensen, whose jaw is wired shut and will have metal plates inserted in his face, is feeling "okay. He's not great," said Piper, who along with her wife has set up a GoFundMe page which so far has raised more than $22,800 to help cover medical costs. "That totally outweighs the bad," she said.
Still, Jensen, who was set to start classes at a community college in two weeks and is considering a career as a park ranger, may take this semester off to recover, Piper said.
"There is no one who deserved this less than Mackenzie," Brian Rieck, manager of Infinite Vapor Minnesota, where Jensen has been working about eight months, tells PEOPLE. "He's incredibly caring."
And he won't let the crime keep him from his love of cycling. Said his mother, "He will get back on his bike."
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