When her teenage son didn't come home Sunday, Chauntyll Allen did what any parent in her position would do. Everything.

She mobilized her friends. She helped start a Facebook page. She plastered the neighborhood with fliers, hoping to grab the attention of someone who knows his whereabouts.

By Tuesday, St. Paul police had joined the search.

Chauntyll said she's growing increasingly worried about her son, Aaron, 18, saying it was unusual for him to be gone so long without at least checking in with her.

Sleep has eluded her since he vanished over the weekend, she says.

"I really just want him to come home," Chauntyll said. "I can't eat, I can't sleep, my heard hurts, my stomach hurts, I really just can't function."

He was last seen early Sunday near the Uni-Dale Mall, in the city's Frogtown neighborhood, one of his favorite hangouts, according to his mother. The security guard who saw him last told Chauntyll that he recognized Aaron from previous encounters.

He never came home the next morning.

He is described as black with a dark complexion, standing 5 feet 11, weighing 230 pounds, with brown eyes and baby dreads. He was last seen wearing an all-black outfit of a visor, T-shirt and shorts.

He works for Circles for Change, a St. Paul-based bicycle and advocacy nonprofit, and has traveled to Seattle and Washington, D.C., to study those city's bike path networks, his mother said. He also filled his time mentoring children, acting as a chaperone on an out-of-state field trip.

"He's always been a responsible kid," Chauntyll said.

But she noticed a change in him last fall after he suffered a psychotic episode, following which he needed a variety of medication. A later run-in with the police also left him shaken, she said.

"This is the first time that this has ever happened, but he has not been the same since the incident," she said.

Police investigators continued their search for Aaron on Wednesday, focusing on areas near the Green Line, which he used to get around, said department spokesman Steve Linders.

"Obviously his family is concerned, and anytime we get a report like this we're concerned about the person's well-being," Linders said. "One thing that we don't do is stop looking for people who are missing, especially if they might be in some kind of danger."

A fixture in the area's activist circles, Chauntyll said she has been impressed with how seriously police have taken her son's case. "The Police Department is putting up his flier at roll call every day," she said, while also singling out Metro Transit.

Over the past few days, friends have made fliers with Aaron's picture to hang around St. Paul. Some of the more than 400 members of the Facebook group, Finding Aaron Allen, volunteered to help get the story of his disappearance out to local media outlets. One member said she'd scoured the roster of every jail in the state for his name.

Someone else posted a photo of Minnesota Lynx star and 2017 WNBA MVP Sylvia Fowles holding a "MISSING" flier on the page.

Now, Chauntyll is just waiting for someone to call saying that Aaron is safe.

"We've got 10-12 cars that are out combing the streets," she said.

Anyone with information is asked to call the Allen family at 612-670-8074 or St. Paul police at 651-291-1111.