Blood-smeared letters were sent to de Blasio's 1 Centre St. office, NYPD Commissioner Ray Kelly said.
Ex-Congressman Anthony Weiner launched @anthonyweiner, nearly two years after "Weinergate."
Liu was scheduled to crisscross the city Sunday with a 137-mile campaign kick-off tour.
Mayor Michael Bloomberg's estimated net worth is now $27 billion.
Former President Bill Clinton and Mayor Bloomberg spoke at Koch's funeral.
Former Mayor Ed Koch died of congestive heart failure about 2 a.m. Friday.
Former Mayor Ed Koch has been moved into intensive care, his spokesman said.
Billionare John Catsimatidis launched his bid for mayor Tuesday.
Former President Bill Clinton dismissed talk that his wife would make a good mayor.
Stringer has been spending more time outside of Manhattan while preparing for a citywide campaign.
Koch is expected to be released as soon as Wednesday following a blood transfusion.
The mayor offered a near-endorsement of City Council Speaker Christine Quinn's expected mayoral campaign.
The 30 Rock star compared the mayoral hopefuls to a date who's trying to get his hands up your blouse.
City Comproller John Liu's poll numbers have sunk after allegations of campaign financing fraud.
Manhattan Borough President Scott Stringer, Public Advocate Bill de Blasio and former Comptroller Bill Thompson shared their visions of the "Future of New York City" during a panel discussion Wednesday.
Get Our Daily New York Newsletter
Thank you for signing up!
Would you like to sign up for additional newsletters?
Thank you for signing up for additional newsletters.