The break-ins began in December but were not detected until Jan. 12 when Jim Hooper, Channel 13's morning news producer, noticed that files listing story projects were missing, said officials at Channel 13. Computer experts deduced that an intruder had rifled the system, Mr. Pyles said.

The police seized a home computer, a Channel 13 computer-user manual and other materials from Mr. Shapiro's apartment in St. Petersburg, Mr. Pyles said. Telephone records indicated that his telephone had been used to enter the Channel 13 computer. The computer at Channel 10 had also been used to gain entry to Channel 13's system, Mr. Pyles said. Computer crime is not unusual, but ''this was unusual because it was involving the media - like media espionage,'' Mr. Pyles said.

Lawyers for Mr. Shapiro and Mr. Cole declined to comment on the charges.

''Shapiro used the computer at Channel 10 to access Channel 13's news computer, and looked at the information it had on it,'' said Mr. Hoyer. ''Everything dealing with the news operation was on it.''

Mr. Hoyer declined to comment on a motive in the case, but he repeated a comment he made to The Columbia Journalism Review in answer to a hypothetical question, noting that television news is very competitive and adding, ''It seems to me it would be rather comforting to know that you're not getting beat.'' Some break-ins appeared to have been made shortly before newscasts, which might indicate that someone at Channel 10 sought a competitive advantage. Slip in Viewer Ratings

Until recently Channel 13 consistently ranked No. 1 in the Tampa television news market, but its ratings have slipped lately, permitting gains at competing stations, Channel 10 and Channel 8.