French prosecutors are also investigating the circumstances that led to the launch of the boat, and the NCA said it is “assisting French police partners with those enquires”.
NCA deputy director Craig Turner said: “Working with colleagues at home and abroad, we are determined to do all we can to identify and bring to justice those responsible for these four tragic deaths.”
Migration minister Mike Tapp said: “Every death in the Channel is a tragedy.
“Our experienced law enforcement teams will continue working relentlessly with international partners to prevent these perilous journeys and bring those responsible to justice.”
He added that the Border Security Act, introduced at the end of last year, has given “officers stronger powers to act earlier and disrupt, intercept and take down the operations of criminal smuggling gangs who bring illegal migrants to our shores”.
