San Francisco ? Federal prosecutors said Friday they would retry a marijuana grower known as the “guru of ganja,” even after a judge urged them to drop the case.

U.S. District Judge Charles Breyer demanded to know who in the Justice Department made the decision to continue pursuing Ed Rosenthal, whose conviction was overturned last year.

Newly appointed U.S. Attorney Scott Schools made the decision, according to Assistant U.S. Attorney George Bevan.

Rosenthal, 62, cannot be sentenced to prison even if he is convicted again because an appeals court upheld the one-day prison sentence imposed by Breyer in 2003. The trial is set for May 14.

Rosenthal was convicted in 2003 of growing hundreds of plants for a city of Oakland medical marijuana program.