Edward Thomas Mann, who is awaiting trial in Montgomery County on charges that he killed three people and wounded 23 others during a shooting rampage at the Bethesda offices of IBM last May, appears to be on a hunger strike, according to officials at the Montgomery County Detention Center.

Mann announced through his wife late last month that he was going on a hunger strike to persuade officials to let him fire his attorney, R. Kenneth Munday. A hearing is scheduled Tuesday in Circuit Court on his request to represent himself.

Samuel Saxton, chief of custody and security at the jail, said Mann has lost 11 pounds in the 22 days since he returned from Clifton T. Perkins Hospital, where he underwent psychiatric tests.

Until recently, Mann was taking three meals a day in his cell "and was sending back an empty tray," Saxton said. Mann shows no signs of loss of strength or physical deterioration, but is now not accepting his meals, although his cellmate is ordering more cookies, candy and ice cream than can be eaten by one man, according to Saxton.

Police said Mann, 38, drove his car through the glass doors of the IBM building last May 28 and went on a 7 1/2-hour rampage.

He later pleaded not guilty by reason of insanity, but a team of doctors at Perkins Hospital declared him mentally competent to stand trial.