3-year-old Elijah Vue was last seen on Feb. 20.
On Monday, Two Rivers Police announced it has a vehicle of interest.
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Police described the car as a beige, four-door 1997 Nissan Altima, with Wisconsin registration beginning with A and ending with 0.
Investigators also asked residents from nearby counties to look for the car in any surveillance camera footage recorded on Feb. 19 from 2 p.m. to 9 p.m.
They are asked to submit the video to a file sharing website.
The child's mother Katrina Baur, and her boyfriend are facing child neglect charges.