The full inquest is due to be held at the Royal Courts of Justice.
"Whilst we believe at this stage Masood acted alone in his execution of the attack, our investigation continues to establish whether there are any others involved in any way and I do emphasize this is a live investigation", Craig Mackey, acting head of London police, said on Wednesday.
The inquest into the death of Khalid Masood opened and adjourned on Thursday (30 March) under the same coroner.
British mother Aysha Frade, pensioner Leslie Rhodes and American tourist Kurt Cochran died of injuries sustained during the rampage.
In total, his attack on Westminster Bridge and the Palace of Westminster, which houses the UK Parliament, lasted 82 seconds.
Thousands of people joined hands in a vigil for the victims exactly a week after the attack on Wednesday, while tributes have been paid across the country.