Engine problems were to blame for leaving adrift a boat packed with Europe-bound African migrants that floated for four months across the Atlantic to the Caribbean Sea off the island of Barbados, investigators said Thursday. Everyone aboard the boat died.

In Spain, police told The Associated Press that authorities have launched two investigations.

The first was begun by Interior Ministry police in Barcelona on a complaint by El-Hadji Sano, a Senegalese man living in the northeastern Spanish city whose brother Malang Sano was believed to have died on the boat. Another investigation is under way in Spain's Canary Islands, located off northwest Africa.

"I want to know what happened," Sano told The Associated Press. "I want justice. Many people have died. They left people in the middle of the sea as if they were animals, and that cannot happen."

The would-be migrants allegedly paid euro1,400 (US$1,800) each to reach Spain, said Barbados police spokesman Barry Hunte. Spanish authorities were seeking a Spanish man they believe organized the trip, the Spanish newspaper El Pais has reported.

Barbadian authorities believe 52 Africans were aboard the rusty 20-foot (6-meter) boat and that it left Senegal on Christmas Eve in a bid to reach Europe. Instead, the boat drifted more than 2,000 miles (3,200 kilometers) west across the Atlantic. It was found on April 29 by a fisherman off the coast of Barbados.

The boat contained the bodies of 11 young men who were virtually mummified by the sun and salt spray. The other passengers apparently were lost at sea.

The boat's engine was not working -- although there was still diesel in it -- and there was evidence that someone had tried to repair it, said Colvin Bishop, assistant police superintendent in Barbados.

It's unclear where all the passengers were from, though officials presume they were Senegalese, Barbados Attorney General Dale Marshall said.

Clues were found on the boat.

One was a note written by one of the migrants and found tucked between the bodies.

"I would like to send to my family in Bassada (Senegal) a sum of money. Please excuse me and goodbye. This is the end of my life in this big Moroccan sea," he wrote. The note appeared to be written by a Senegalese man named Diao Souncar Dieme, said Marshall. The names Ibrahima Dieme and Omar Badje were mentioned in the note.

The name S.V. Cabafumo also appeared on a jacket, and an Air Senegal plane ticket was issued to a person called Sane Sanah, Hunte said.

An Interpol team has examined the boat and the bodies, which have been moved to a Barbados funeral home. Barbados has asked for fingerprint experts, pathologists and a dentist to investigate further, Marshall said.

For his part, Sano said he will continue to seek justice for his brother.

"I think of my brother all the time ... and every time I think about what happened I get very angry," he said.

With transit routes to Europe through Morocco being gradually sealed, migrants are taking to the seas farther down the coast of northwest Africa, some traveling in overcrowded fishing boats more than 1,000 miles (1,600 kilometers) in stages to reach Europe.

The boats often get lost or break down, drifting helplessly in the Atlantic or capsizing in rough seas.

Authorities on the Canary Islands say they have intercepted nearly 7,000 migrants since January, compared to 4,751 in 2005.

More than 1,000 are believed to have perished attempting the journey from Africa to the Canary Islands since December, according to the Red Cross in Mauritania, a favored departure point for the boats.

Ismaila Diallo, of the Casamance region in southern Senegal, said his 19-year-old brother died last year traveling on a boat that sunk as it headed to the Canary Islands. Weeks passed before the family learned he had died.

"It's horrible. When we heard about the death of my brother, it was unbelievable," he said. "I didn't think he was going to die in this way."