The man suspected of firebombing the Border Force immigration centre in Dover lived almost 120 miles away in High Wycombe, police have said.
The suspect, who was later found dead at a nearby petrol station, was 66 years old and from the town in Buckinghamshire, Kent Police said.
Two people inside the migrant centre reported minor injuries. The man’s name has not been released.
Officers from Kent Police and Thames Valley Police are searching a property in High Wycombe after two to three incendiary devices were hurled at the migrant centre.
The attacker was described by witnesses as a white man wearing a striped top, who drove up to the centre in a white Seat four-wheel drive vehicle.
The attack prompted around 700 people to be moved to the Manston asylum processing centre in Kent for safety reasons as police investigated.
The incident came after almost 1,000 migrants arrived in the UK after crossing the Channel on Saturday.
Immigration minister Robert Jenrick said in a tweet on Sunday that he had visited Manston following growing concerns about its poor conditions.
The allegedly overcrowded facility left independent chief inspector of borders and immigration David Neal “speechless” earlier this week.
Mr Neal told MPs that Manston was originally meant to hold between 1,000 and 1,600 people but there were 2,800 at the site when he visited on Monday, with more arriving.
Veteran backbencher Sir Roger told Sky News there are now more than 4,000 people at the Manston facility, describing the situation there as a “breach of humane conditions”.
And speaking to BBC Radio 4’s Today programme, he said: “There are simply far too many people and this situation should never have been allowed to develop, and I’m not sure that it hasn’t almost been developed deliberately.”
The Home Office is struggling to find hotel accommodation, he said, adding that he now understands that this is a policy issue and a decision was taken not to book additional hotel space.
“That’s like driving a car down a motorway, seeing the motorway clear ahead, then there’s a car crash, and then suddenly there’s a five-mile tailback.
“The car crash was the decision not to book more hotel space,” he said.
The mounting problems at Manston are adding pressure on embattled home secretary Suella Braverman who is expected to be questioned about the problems at the site when she appears in the House of Commons later today.
Additional reporting by PA
