Federal prosecutors are requesting that defense attorneys for Boston Marathon bombing suspect Dzhokar Tsarnaev notify them in writing by next month if they plan to introduce any evidence that Tsarnaev had a mental illness.
In a document filed Friday in U.S. District Court, prosecutors said the defense should disclose any such plans by May 7, a date previously set for pre-trial motions in the case.
The government said it was seeking notification of plans to present "expert evidence relating to a mental disease or defect or any other mental condition ... which bears on either the issue of guilt or the issue of punishment."
A spokeswoman for Miriam Conrad, one of Tsarnaev's lawyers, said she declined comment.
Tsarnaev has pleaded not guilty to 30 federal charges in connection with last year's attack.