(CBS) — A Minnesota man is in Chicago looking for his missing son: a wheelchair-bound man who may be disoriented and was last seen in this area.

Tom Brunberg is the father of 43-year-old Mark Brunberg – who was driving in his van from Tennessee to Minnesota for a family get-together. He says his son called collect on Friday morning, possibly from LaGrange.

“He indicated he lost his wallet or it was stolen,” said Tom Bruneberg.

And then he’s believed to have taken the train into Chicago – and borrowed the cell phone of a CTA employee to call his father again to say he was going to go to either LaGrange or Orland Park.

That employee tells WBBM he last saw Mark Brunberg getting off the Orange Line at Roosevelt Road.

Tom Brunberg says his son has been paralyzed since a bicycling accident in 1995. He’s in a wheelchair and may be suffering from dementia.

The car Mark Bruneberg was driving is a white Mercury Villager mini-van with Tennessee plate 305DD08. Call Carver County Sheriff (MN) Tipline: 952-361-1224 or Deputy Adam Hasting, Badge #836, Cell: 952-451-2725.

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