Emergency services rescued and transported about 41 people from a semi-sunken dinghy.
Defence lawyers continue to press for deportation of the twelve in custody.
Twelve of 23 people detained as of midday Saturday.
The woman told rescue workers that 40 migrants were aboard the dinghy
The migrants faced a seven-hour voyage in dire conditions to the Iberian Peninsula.
In the last week National Police have intercepted a total of six people trying to fly to the United Kingdom with fake passports
Fifty detentions in all have been made as a result of National Police controls.
A link had been made between drug dealing and a group bringing immigrants from Algeria.
A group of Algerians were engaged in drug dealing and organising immigrant boats from Algeria.
Some six hundred people had entered Spain because of the illegal immigration operation.
The men were working in poor conditions and being paid a tenth of what had been promised.
Four of the five people arrested were Albanian.
The Spanish interior ministry says that so far this year the arrival of immigrants by sea has gone up by 45%.
Over 100 armed police officers were involved in the evening raid against drugs and illegal immigration.