With Katie Couric drawing him out, New York City Mayor Michael Bloomberg
agreed the Times Square car bombing was likely "homegrown" as he
proceeded, in an interview excerpt run on Monday's CBS Evening News, to speculate
it could have been placed by "somebody with a political agenda who
doesn't like the health care bill or something. It could be
Could be "anything," but the first thing Bloomberg thinks of are those who don't like ObamaCare, presumably conservatives or Tea Party activists.
Audio: MP3 clip 
From part of Couric's interview with the mayor aired on the Monday, May 3 CBS Evening News:
KATIE COURIC: Law enforcement officials don't know who left the Nissan Pathfinder behind, but, at this point, the mayor believes the suspect acted alone.
MAYOR MICHAEL BLOOMBERG: If I had to guess - 25 cents - this would be exactly that, somebody-
COURIC TO BLOOMBERG: A home-grown?
BLOOMBERG: Home-grown, maybe a mentally deranged person or somebody with a political agenda that doesn't like the health care bill or something. It could be anything.