The bomb used in the Liverpool Remembrance Sunday attack was a homemade explosive with ball bearings attached to it and could have caused “significant injury or death”, police have said.

Emad Al Swealmeen, 32, died when the taxi he was a passenger in exploded outside the Liverpool Women’s Hospital just before 11am on Sunday.

In an update on Friday, Assistant Chief Constable Russ Jackson, head of Counter Terrorism Police North West, said: “Although there is much scientific work to do on the device to determine what made it up, we have learned a great deal over the past five days.

“It was made using homemade explosive and had ball bearings attached to it which would have acted as shrapnel.

“Had it detonated in different circumstances we believe it would have caused significant injury or death.

“We still do not know how or why the device exploded when it did, but we are not discounting it being completely unintentional, and it is a possibility that the movement of the vehicle or its stopping caused the ignition.

“We are spending considerable time seeking to understand the way the purchases for the ingredients to make the device were made.

“This is complicated because purchases have spanned many months and Al Swealmeen has used many aliases.

“We are confident however that in time we will get a full picture of what purchases were made and how, and if anyone else was involved or knew what Al Swealmeen was up to.”

He said there was no link between the incident and the Manchester Arena bombing in 2017, which he said involved a different type of device.

Taxi driver David Perry escaped from the explosion with injuries.

Mr Jackson said “significant progress” was being made in the investigation, which includes ongoing searches at addresses in Sutcliffe Street and Rutland Avenue in Liverpool.

He said: “Officers spoke with the brother of Al Swealmeen yesterday evening and this has given us an insight into his early years and an understanding of Al Swealmeen’s life and his recent state of mind which is an important line of investigation.

“We are grateful for members of the public who knew him and have contacted us.”

While an Islamist plot is one line of inquiry, the PA news agency understands investigators are still keeping an open mind and the motivation is still yet to be established.

Police and security services are still thought to be working on the current understanding that the hospital was the intended target.

The asylum seeker, who had converted to Christianity, reportedly arrived in the UK from the Middle East in 2014 and had an application for asylum rejected the following year, but had a fresh appeal ongoing at the time of his death.

Earlier this week, Home Secretary Secretary Priti Patel claimed he had been able to exploit Britain’s “dysfunctional” immigration system by staying in the country.

Police said Al Swealmeen had been renting the property in Rutland Avenue, near Sefton Park, since April and was making “relevant purchases” for his bomb from at least that time.

Read more: Liverpool attacker had been buying bomb parts since April

The Liverpool bomber had been buying bomb components since at least April, police have revealed.

Assistant Chief Constable Russ Jackson said that Iraq-born Emad Al Swealmeen had rented a property in Liverpool seven months ago and had started making “relevant purchases” for his homemade bomb “at least” since that time.

In an update issued on Wednesday he said: “A complex picture is emerging over the purchases of the component parts of the device, we know that Al Swealmeen rented the property from April this year and we believe relevant purchases have been made at least since that time.

“We have now traced a next of kin for Al Swealmeen who has informed us that he was born in Iraq.”

He also said that the 32-year-old asylum seeker had suffered from periods of mental illness that will “form part of the investigation and will take some time to fully understand”.

Mr Jackson added: “There is much comment in the media about Al Swealmeen and it is clear that he was known to many people. We continue to appeal for people who knew him, especially those who associated with him this year as we try and piece together the events leading up to this incident and the reasons for it.

“At this time we are not finding any link to others in the Merseyside area of concern but this remains a fast moving investigation and as more becomes known we cannot rule out action against others.”

Earlier, Home Secretary Priti Patel claimed that Al Swealmeen, who reportedly arrived in the UK from the Middle East in 2014 and had an application for asylum rejected the following year, had been able to exploit Britain’s “dysfunctional” immigration system by staying in the country.

She said the system was a “complete merry-go-round” with a “whole industry” devoted to defending the rights of individuals intent on causing harm.

Christian convert Al Swealmeen died in the blast in a taxi outside Liverpool Women’s Hospital shortly before 11am on Remembrance Sunday.

Concerns have been raised that some asylum seekers in the city may have pretended to convert to Christianity in order to bolster their visa applications.

Liverpool Cathedral, where Al Swealmeen was baptised in 2015 and confirmed in 2017, said that asylum seekers who convert would be expected to be “closely connected” with the congregation for at least two years before staff would support a visa application.

A spokesman said: “Liverpool Cathedral has developed robust processes for discerning whether someone might be expressing a genuine commitment to faith.

“These include requirements for regular attendance alongside taking part in a recognised Christian basics course. We would expect someone to be closely connected with the community for at least two years before we would consider supporting an application.”

According to newspaper reports, Ms Patel told reporters on her flight to the US capital that the case showed why the Government was right to reform the asylum system.

“The case in Liverpool was a complete reflection of how dysfunctional, how broken, the system has been in the past, and why I want to bring changes forward,” she was quoted as saying.

“It’s a complete merry-go-round and it has been exploited. A whole sort of professional legal services industry has based itself on rights of appeal, going to the courts day-in day-out at the expense of the taxpayers through legal aid. That is effectively what we need to change.”

A couple who took in Al Swealmeen after his appeal against the asylum ruling was rejected insisted that he had been an “absolutely genuine” Christian with a “real passion for Jesus Christ”.

Malcolm and Elizabeth Hitchcott said they had been contacted by Al Swealmeen, who also used the name Enzo Almeni, in 2017 when he was “desperate” for somewhere to stay.

Mr Hitchcott told BBC Radio Merseyside: “He arrived here on April 1 2017. He was with us then for eight months, and during that time we saw him really blossoming in regards to his Christian faith.

“He really had a passion about Jesus that I wish many Christians had, and he was ready to learn.

“He was keen on reading his Bible and every night we used to pray – my wife and him, and if there was anybody else in the house – we prayed for half an hour or so and studied the scriptures.

“He was absolutely genuine, as far as I could tell. I was in no doubt by the time that he left us at the end of that eight months that he was a Christian.”

It is understood however that an Islamist plot is one line of inquiry being considered by police, although investigators are keeping an open mind and the motivation is yet to be established.

Official sources told the PA news agency the current understanding is still that the hospital was the intended target.

The inquiry is examining, among other possibilities, whether the main charge on the device failed to explode and if the homemade explosive TATP was used.

Searches have been carried out at the property in Rutland Avenue that had been rented since April by Al Swealmeen, and a second property in Sutcliffe Street, where officers believe he previously lived.

The incident has been declared a terrorist attack and the UK terror threat level has since been raised from substantial to severe, meaning an attack is “highly likely” rather than “likely”.