MADRID: Spanish police said Wednesday that they had arrested 19 people accused of murder and torture aboard a migrant boat heading from Senegal to the Canary Islands, where at least 50 people went missing.

The wooden vessel was rescued adrift south of Gran Canaria in the Atlantic on August 24 with 248 survivors on board, the Spanish National Police said.

Authorities believe the boat originally carried around 300 people, and many of the missing are presumed to have been thrown overboard during the 11-day voyage.

Survivors told investigators that several fellow passengers began “attacking dozens of people, beating and mistreating them in various ways,” police said in a statement.

“In some cases, they threw migrants into the sea alive and refused to rescue those who fell in by accident,” it added.