Two survivors and eight bodies found but 44 people remain missing.
The US Coast Guard (USCG) initially assisted police in searching for about 56 Haitians reported missing, but was eventually told its help was no longer needed, said Luis Diaz, USCG spokesman.
The capsized boat was seemingly set for the US, 900 km away.
Every year hundreds of Haitians make illegal sea voyages to other countries on overcrowded boats, in an attempt to escape violence and poverty.
Since 2001, a total of almost 400 people have been reported dead or missing at sea as on travels from Haiti, Cuba and the Dominican Republic to the US.
In March, a USCG crew recovered five bodies after a sailing freighter with 56 Haitians aboard caught fire and capsized off the Dominican Republic.
Since January, 909 Haitians have been interdicted by the USCG while traveling illegally to the US.