When the plaintiff does not know the name of the defendant, the defendant may be designated in any pleading or proceeding by any name. When the defendant's true name is discovered, the pleadings or proceedings may be amended accordingly.
Mont. Code Ann. § 25-5-103
Suing party by fictitious name
En
Official source: Montana Code Annotated (Montana Legislature). Reproduced from public-domain Montana statutes; confirm against the official source for the current text. Not legal advice.