And now, a short lesson on how not to communicate with a law enforcement official.

Even before the Sept. 11, 2001, terrorist attacks and deadly anthrax mailings, it was always a bad idea to include suspicious-looking white powder in an envelope addressed to a prosecutor such as Frederick County State's Attorney Scott L. Rolle. The one Rolle received said, "TAKE PENACILIN NOW. HAVE A NICE DAY."

Also -- and here we must go to the charging papers filed in Frederick County District Court -- it is probably not good thinking to include a signature, inmate number and a return address.

But authorities say that is exactly what Robert D. Turner of Baltimore did.

"It was helpful to us, to discover who did it, shall I say," Rolle said yesterday in a telephone interview. Three weeks earlier, Rolle said, Turner sent another letter threatening to kill Rolle and his family when Turner left jail.

Rolle said that first letter, which did not contain any suspicious substance, was signed "Anakin" -- apparently a reference to the youthful Darth Vader in the "Stars Wars" movies. It contained a return address but no other name.

Court papers filed by Sheriff's Detective Richard A. Rochford Jr. on Wednesday say Turner, 32, mailed the powder-filled letter to Rolle -- addressed as "Head States' Attorney" -- from the Maryland Correctional Adjustment Center in Baltimore.

Mark Vernarelli, spokesman for the Maryland Department of Public Safety and Correctional Services, said that Turner is in prison for homicide. If he serves his entire sentence, he would be released in 2047.

The letter, which was placed in a sealed envelope after its arrival Sept. 3, was examined by a hazardous materials team and determined to be safe, the charging papers say.

Turner was charged with threatening a state official and making a phony destructive device with the intent to terrorize, the papers say.

Turner also admitted to sending a very similar threatening letter with white powder to the county's Circuit Court clerk last October, the charging documents say.

Those charges are pending.