Three people have been arrested on suspicion of immigration offences after five people including a child were killed as they tried to cross the Channel.
The National Crime Agency said investigators are questioning two men from Sudan aged 19 and 22, and a third 22-year-old suspect from south Sudan over the tragedy.
They were arrested on suspicion of facilitating illegal immigration and entering the UK illegally.
Three men, a woman and a girl were killed when a dinghy carrying more than 100 people got into difficulty after setting off from Wimereux at around 6am.
Some 49 people were rescued but 58 others refused to leave the boat and continued their journey towards the UK, the French coastguard said in a statement, with several other boats later embarking on the crossing.
The surviving boat passengers have already been interviewed and are expected to be spoken to further in the coming days.
Craig Turner, deputy director of investigations for the National Crime Agency said: "This tragic incident once again demonstrates the threat to life posed by these crossings and bring into focus why it is so important to target the criminal gangs involved in organising them.
"We will do all we can with partners in the UK and France to secure evidence, identify those responsible for this event, and bring them to justice."
More than 400 migrants arrived in the UK after crossing the Channel as the tragedy off the coast of northern France unfolded, just hours after Parliament passed legislation aimed at getting the Government's plan to give asylum seekers a one-way ticket to Rwanda off the ground.
Home Office figures show 402 people made the journey in seven boats that same day after an eight-day break in activity in the Channel, which suggests there was an average of around 57 people per boat.
Young children and babies were among those seen being brought ashore in Dover, Kent, while witnesses described how crews carried someone on a stretcher from a lifeboat to an ambulance.
The latest crossings take the provisional total for the year so far to 6,667 - 20% higher than this time last year (5,546) but slightly lower (down 0.4%) than the figure recorded at this stage in 2022 (6,691).
Campaigners said the Rwanda plan will not save lives as they lamented the news of more deaths as a result of the treacherous journey and called for the Channel not to become a graveyard for children.
But Prime Minister Rishi Sunak said the incident underscores the need for the deterrent the Government hopes sending migrants to the east African nation if they arrive illegally in the UK will bring.
The National Crime Agency (NCA) said it would be supporting the French investigation into the deaths with UK police and Border Force.
Some 29,437 made the journey in 2023, down 36% on a record 45,774 arrivals in 2022.