Family of missing Madeline Kingsbury offer $50k reward after ‘dedicated mother’ vanishes before school pickup

The sister of a Minnesota woman who went missing last week under "suspicious" circumstances has appealed for help from members of the public.

Madeline Kingsbury, a 26-year-old mother of two children, was last seen on 31 March.

According to the police, Ms Kingsbury and the father of her children returned to their home in Winona after dropping off the kids at daycare on Friday.

The father said he left for work in Ms Kingsbury’s van, around 10am local time, and returned later in the day only to find his wife gone.

Ms Kingsbury did not show up for work that day or respond to "numerous" calls and messages from friends and family. She also failed to pick up her children from daycare that afternoon, which the police said was "extremely out of character for her".

"We believe Maddi's disappearance is involuntary, suspicious and we are all concerned for her safety," said Winona police chief Tom Williams.

Ms Kingsbury's elder sister, Megan, addressing the media on Wednesday, offered a $50,000 reward for information on the missing woman's whereabouts.

"To be honest I don’t know everything,” she said about the current investigation into her sister’s disappearance.

“Madeline is many things. She’s a mother, sister, daughter, best friend, granddaughter, niece. It’s a long list.

“Madeline is a hard-working and dedicated mother. Family is everything to her and she’s grown into an impressive and beautiful young woman.

“Please help us find Madeline. 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.”

Authorities obtained surveillance video showing a van matching the description of Ms Kingsbury's – a 2014 dark blue Chrysler minivan – leaving and returning to the area of her house between 10am and 1.30pm on Friday.

"Based on the investigation, we know that the children were dropped off at the daycare and that the van returned home," said Mr Williams.

The Fillmore County Sheriff’s Office has requested assistance from residents in Winona and nearby townships to search their property. “We are asking that you search your acreage, wooded property, outbuildings, vehicles and trails for anything suspicious that may help find Madeline."