"dubious case" is a correct and usable phrase in written English.
You can use it to describe a situation or scenario that is questionable and open to doubt. For example, "The judge found the evidence in the defendant's dubious case to be inconclusive."
Richard Prince is a more dubious case.
The Wayward Press....West Coast editors have not been entirely oboveboard in the way they have peddled this dubious case to their readers.
Witness the way the Government shaped intelligence material to support its dubious case for war and how, subsequently, it disgracefully concealed Dr Kelly's true role.
So, he argues, nobody should fuss about the past.That was the thrust of the dubious case Mr Singh presented to journalists, on September 27th, as he flew home from New York.
REUTERS A Dubious Case Found Lawyers Eager to Make Some Money | In Paul Ceglia's case against Facebook, his lawyers vouched for a client who is now charged with a "blatant forgery," writes Andrew Ross Sorkin in the DealBook column.
Even in the dubious case that he could throw an election, which is increasingly hard, Enrique Peña Nieto, Mexico's fledgling president, has too much to lose by resurrecting the ghost of Mr Salinas.
Intraoperative completion arteriography was routinely performed for eversion endarterectomy and only in dubious cases with other techniques.
First, it must be understood that presidents have used their absolute pardon power in dubious cases from the beginning.
Here the bureaucrats admit that they are pushing through dubious cases in order to meet the deadline of 20 countries by the end of the year.
That trend can be traced back to 1950s US series The Court Of Last Resort, in which dubious cases were re-enacted for TV.
There is no manual that Forcelli could write that would stop police departments from pressuring detectives for results or prosecutors from taking on dubious cases.
