LONDON (Reuters) - Irish police said on Saturday they had arrested a man in his 20s from Northern Ireland on suspicion of involvement in the deaths of 39 people found in the back of a truck near London on Wednesday.

Irish state broadcaster RTE said the man was arrested at Dublin’s port on Saturday morning after arriving on a ferry from France, and that police wanted to question him about the movements of the container in which the bodies were found.

British police have already arrested four people in connection with the incident.