A series of out-of-character events for a Minnesota woman, who hasn't been seen since March 31, has family and police worried about her safety and calling for help to find her.

Madeline Kingsbury, a 26-year-old mother of two young children, didn't show up for work after dropping off her kids at day care with the children's father the morning she vanished, police said, and she didn't pick them up that afternoon.

Friends and family posted on social media that they've been frantically trying to reach her for days to no avail, and they are offering a $50,000 reward.

Police also found her phone, wallet, ID and jacket that she wore earlier in the day, Winona, Minnesota, Police Chief Tom Williams said during a Wednesday afternoon press conference.

MISSING LAWYER CIERA BRELAND'S MOM BELIEVES SHE WAS KILLED

madeline kingsbury

Minnesota mother Madeline Kingsbury, 26, was last seen dropping her children off at day care on March 31. (Madeline Kingsbury / Facebook)

That is "very unlike her," said Williams, who was surrounded by Kingsbury's family members dressed in "missing person" sweaters with pertinent phone numbers.

"Based on all of this, we believe Maddie's disappearance is involuntary, suspicious, and we are all concerned for her safety," the chief said.

NURSE REBECCA BLIEFNICK SHOT DEAD; COPS SEARCH ESTRANGED HUSBAND'S HOUSE

Kingsbury's sister's voice cracked during an emotional plea to "help us find Madeline."

"Madeline is many things," Megan Kingsbury said. "Madeline is a hard-working and dedicated mother. Family is everything to her, and she’s grown into an impressive and beautiful young woman."

madeline kingsbury

Minnesota mother Madeline Kingsbury, 26, was last seen dropping her children off at day care on March 31. (Madeline Kingsbury / Facebook)

"The children need their mother. We need our daughter, our sister, our aunt, our best friend back. We just want to find her, so, thank you."

The father of Madeline's children told law enforcement that he was with Madeline until about 10 a.m. on March 31 and "returned later that day, and Maddie was not home," the police chief said.

SCHOOL SUICIDE: MOTHER OF 11-YEAR-OLD DISCOVERS OMINOUS CELLPHONE RECORDING 

Screenshots of a Facebook post that he purportedly wrote said he was with Madeline until 10:30 a.m. the day she went missing, left to run errands, and she was gone by the time he returned that afternoon.

That post has since been deleted or can't be viewed.

Fox News Digital reached out to the children's father but hasn't heard back, and a Kingsbury family spokesperson told Fox News Digital that, at this point, they didn't want to divulge details about the children's father.

The family's focus is finding Madeline, and they have been out with law enforcement searching for her.

BUS DRIVER ‘WON'T TAKE BACK’ PROFANITY-LACED RANT AT STUDENTS CAUGHT ON CAMERA

Williams said there's no suspect at this point, but the case is actively being investigated as a "missing person with the prospect of foul play."

Further complicating the case is surveillance video that picked up Madeline's 2014 dark-blue Chrysler leaving her home and returning between 10 a.m. and 1:30 p.m. on March 31, according to the chief, who said he couldn't say who was driving.

madeline kingsbury

Minnesota mother Madeline Kingsbury, 26, was last seen dropping her children off at day care on March 31. (Winona, Minnesota, Police Department)

The van has been parked in her driveway since 1:30 p.m. March 31, and "nothing indicates Maddie left on foot or in another vehicle," the chief said.

Winona police and the Fillmore County Sheriff's Office are asking everyone in and around the areas highlighted above to check all security cameras and doorbell cameras, walk their properties, check all buildings and call the Winona Police Department at 507-457-6302 with any information or tips.

CLICK HERE TO GET THE FOX NEWS APP

Police are also asking that everyone in those areas to save any video footage from March 31 to April 1, "regardless of if you see something or not," Williams said.

Anyone who wants to remain anonymous can submit tips at www.crimestoppersmn.org or at 800-222-8477.