Counter-terrorism officers in Britain have traced a relative of the Liverpool bomber and are due to speak to them, a police chief said on Thursday, according to the BBC.
Assistant Chief Constable Russ Jackson said Iraq-born Emad Al Swealmeen had been officially named as the taxi passenger killed in Sunday's blast.
Searches were continuing at Liverpool Women's Hospital and two homes where the asylum seeker had lived, he said.
His home prior to the blast was the "main focus" of searches, he added.
Al Swealmeen was a passenger in a taxi when his homemade device exploded on Sunday outside the maternity hospital.
A post-mortem examination found he died from injuries caused by the explosion and fire.
The taxi driver, David Perry, escaped seconds before his car was engulfed in flames and has since been discharged from hospital.
Court records showed that Al Swealmeen was first refused asylum in 2014 and also lost further appeals in 2015.
Jackson said Al Swealmeen had suffered from periods of mental illness which will "form part of the investigation".
Following Sunday’s blast, British authorities raised the country's terror threat level to its second-highest level.
The Liverpool attack occurred weeks after UK lawmaker David Amess was stabbed multiple times during a visit to a church by Ali Harbi Ali, who considered himself affiliated with the Islamic State (ISIS) terrorist organization.
Britain has been hit by a series of terrorist attacks in recent years.
In February of 2020, a man stabbed and wounded three people in south London before being shot dead by police.
Three months earlier, three people were killed in a terrorist attack at London Bridge.
In May of 2017, 22 people were killed when terrorist Salman Abedi detonated a bomb at the end of an Ariana Grande concert at the Manchester Arena.
London Bridge was also the scene of a terrorist attack in June of 2017 in which ISIS-inspired attackers ran down people on the bridge, killing two. They then proceeded to stab several people to death in nearby Borough Market.