UK police find 39 bodies in cargo truck, driver arrested

*RESENDING UPDATING SCRIPT DETAILS BASED ON NEW POLICE INFORMATION*

A grisly discovery in the middle of night, and now a murder investigation.

Police have discovered 39 bodies inside a cargo truck container at an industrial park in Essex, England.

One teenager and the rest adults. The driver -- who has not been publicly identified -- is under arrest.

Essex's deputy chief of police, Pippa Mills:

(SOUNDBITE)(English) ESSEX POLICE DEPUTY CHIEF CONSTABLE, PIPPA MILLS, SAYING:

"At this stage, we have not identified where the victims are from or their identities, and we anticipate this could be a lengthy process."

While it's not yet clear who the dead are - it is believed that the truck's trailer traveled from Belguim and docked in the UK early on Wednesday (October 23) morning.

The grim scene was uncovered shortly shortly before 1:40 a.m. on Wednesday morning, after ambulance services made a call to Essex Police.

Police say the driver is a 25-year-old man from Northern Ireland.

For years immigrants have attempted to traverse the UK and EU illegally by stowing inside the cargo, sometimes with fatal results.