In addition, a 46-year-old Northern Irish man, who was arrested Friday at Stansted Airport, has been released until Nov. 13, police said.
"All three had been questioned on suspicion of manslaughter and conspiracy to traffic people," Essex police said in a news release.
The driver of the truck, Maurice Robinson, 25, of Craigavon, Northern Ireland, is scheduled to appear in court Monday, police said. He has been "charged with 39 counts of manslaughter, conspiracy to traffic people, conspiracy to assist unlawful immigration, and money laundering," the news release said.
Update 2:55 p.m. EDT Oct. 25: Essex police said Friday that four people have been arrested as part of the investigation into the discovery earlier this week of dozens of bodies in a truck container.
Deputy Chief Constable Pippa Mills did not release the suspects' names. She said authorities apprehended a 48-year-old man from Northern Ireland on Friday at London Stansted Airport on suspicion of conspiracy to traffic people and suspicion of manslaughter.
Authorities have also arrested two 38-year-old's from Warrington, identified as a man and a woman, suspected of the same crimes. The 25-year-old driver of the truck remained in custody Friday on suspicion of murder, police said.
"This is a fast-moving investigation involving significant police resources dedicated to finding out the truth about what happened to the 39 people found dead in the lorry on Wednesday," Mills told reporters Friday. "We owe it to those who have died to get this investigation right."
Original report: The driver arrested after English authorities discovered dozens of bodies in a truck container has been identified, multiple news outlets are reporting.
According to CNN, the BBC and ITV News, authorities are questioning Mo Robinson, of Northern Ireland's County Armagh, after finding 39 bodies early Wednesday at an industrial park in Grays.
Essex police have not publicly released the suspect's name, saying only that they arrested a 25-year-old Northern Irish truck driver "on suspicion of murder." He was still in custody Thursday morning, authorities said.
"We want to be clear – we have not speculated about the identity of this man, and we will not do so," police said in a news release Thursday. "We can confirm that three properties in County Armagh have been searched in connection with our investigation."
Police are still trying to identify the victims, who include eight women and 31 men, the news release said. Although investigators initially said one of the dead was a teenager, officials later clarified that she was actually "a young adult woman." All 39 people killed "are believed to be Chinese nationals," police said.
Investigators said the truck arrived Saturday in Holyhead, England, after traveling from Dublin, Ireland, according to the release. The truck picked up the trailer, which had come to Purfleet, England, via Zeebrugge, Belgium, about 12:30 a.m. local time Wednesday and left about 35 minutes later. About 1:40 a.m., police responded to reports that bodies were found in the container, authorities said.
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