Anyone with missouri law knowledge?

Lacy
One of my friends had the police bust in his door 3 nights ago, he has no knowledge of any warrants in his name and we even checked online and the site we use didn't show anything. However, his sister is married to a city cop here in our town, and they apparently have their own accounts on this site. His sister showed him a screenshot of a warrant from her husband on his account. My question is: is it legal for police, whether it be sate, county, or city, to issue a warrant, and the "fugitive" have no knowledge? We have called the county court house, my fiance is good friends with a county and city cop, and asked them and they have both told him there is no warrant. I'm just confused on whether this is legal or not.