No, once parties are dismissed from a lawsuit, you cannot serve them with written discovery in the form of Requests for Admissions, Interrogatories, or Requests for Production of Documents.
You may be able to take their depositions (which is very expensive since you will need a court reporter) and can potentially request that they produce certain records by having subpoenas issued and served with your requests. You can also try to informally interview them or have somebody else do so, but they are under no obligation to agree to that.
Also, depending on who these people are, if they are employees or officers of the defendant corporation, there may be ways to craft interrogatories to the corporation so that the corporation must get the input of those persons in order to provide the responses.
Attorney Darrow is correct.
Once a party is dismissed, you can no longer serve them with written discovery such as Requests for Admissions, Interrogatories, or Requests for Production of Documents. However, you can subpoena witnesses for deposition, and ask them to produce documents at the deposition.
Frank W. Chen has been licensed to practice law in California since 1988. The information presented here is general in nature and is not intended, nor should be construed, as legal advice for a particular case. This posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, please consult with your own attorney.
If the Defendant is represented by counsel, the discovery request - interrogatories must be served on counsel for the defendant and any other parties/counsel who have appeared in the matter. If they are not answered within the time period allowed by law (30 days if personally served or 35 if served by mail) then you can make a motion to the court compelling them to answer the interrogatories. You can not serve interrogatories on non-parties. You can serve a deposition subpoena requiring them to sit for a deposition before a court reporter and answer questions under oath.