LONDON (AP) — A truck driver accused in the deaths of 39 Vietnamese migrants whose bodies were found inside a refrigerated container in England has pleaded guilty to manslaughter.

Maurice Robinson, 25, of Craigavon in Northern Ireland, entered the plea at Central London Criminal Court on Wednesday.

The bodies of the 39 people were found Oct. 23 in the town of Grays, east of London. Police investigating the case found the victims were all from Vietnam and ranged in age from 15 to 44.

The 31 men and eight women are believed to have paid people traffickers to smuggle them into England. Police say they died of a combination of a lack of oxygen and overheating in an enclosed space.