spectators have been told to bring no backpacks, ruch sacks, strollers or costumes. david gould is running his first boston marathon. i think it s a lot safer but there s still a bigger risk than last year because, you know, they knew it happened once, it could happen again. reporter: that is the worry here, a copycat attack. the potential target zone extended more than 26 miles through eight cities and towns somebody said it may be the safest place in america tomorrow. reporter: massachusetts governor duval patrick appeared on face the nation this morning. we practiced different scenarios so i think we re very, very well prepared. reporter: last year s twin explosions near the finish line pressure cooker bombs detonated 13 second as part, rattled the city. three people were killed. more than 260 injured. noreen beiro was crossing the finish line as the second explosion went off. she was uninjured. so the first one was startling, the second one was ominous. yes, yes.