A man forced his way into a house in Bristol with an “explosive device” a few minutes before a blast that killed his ex-partner and himself.

Police said they were treating the death of the woman, whom they believe to be 35-year-old Jo Shaw, as homicide and named the man who died as her former partner, Ryan Kelly, 41.

They said they believed the explosion early on Sunday had been caused deliberately but stressed it was not thought to be linked to terrorism.

Avon and Somerset police said they received a call from another person inside the house at 6.17am on Sunday reporting a “domestic-related” incident.

At about 6.30am, the caller told police they thought the man had an explosive device on him. Two minutes later the blast happened.

The force has referred itself to the Independent Office for Police Conduct (IOPC) because other domestic incidents had been reported prior to Sunday.

Three more people, including the person who called police, were treated for minor injuries and did not need to stay in hospital.

Supt Matt Ebbs said: “We know people will be shocked and upset to learn of the horrendous events that happened on Sunday morning.

“Jo’s death has been officially recorded as a homicide based on the information known to us at this time. We are not looking for anyone else in connection with her death.

“We know everyone’s thoughts and sympathies will be with her devastated family. Specially trained officers are providing them with updates and support.”

The police said the person who called them said the man who had forced his way in was known to them. The caller remained on the line as police were dispatched to the house in Sterncourt Road, Frenchay.

The first officers arrived at the property two minutes after the explosion and were joined by the fire and ambulance services shortly afterwards.

The force said: “We can confirm a mandatory referral will be made by our professional standards department to the Independent Office for Police Conduct (IOPC).

“This is on the grounds of the deaths occurring following previous police contact, specifically other domestic incidents being reported to us prior to Sunday.”

Officers worked with Bristol city council to evacuate people staying in neighbouring properties as a precaution and set up a temporary rest centre.

Searches were carried out by the army’s explosive ordnance disposal team and specialist police officers to ensure the area was safe before the cordon was reduced on Sunday night and almost all residents were allowed to return home.

A search of a separate address in Speedwell linked to Kelly concluded over the bank holiday weekend. No evacuations were required there.

Ebbs added: “Police activity continues to be carried out at the property in Sterncourt Road and we expect this will take several days to be completed.

“We would like to reassure the public there is not believed to be any wider risk to safety and this is not being treated as terrorism-related.

“As previously stated, we believe the cause of the explosion to be deliberate. Analysis work of the explosive device has not yet been completed.

“We will share all details of our inquiries with the coroner so they can make a final determination around how the deaths occurred in due course.”

In the UK, call the national domestic abuse helpline on 0808 2000 247, or visit Women’s Aid. In the US, the domestic violence hotline is 1-800-799-SAFE (7233). In Australia, the national family violence counselling service is on 1800 737 732. Other international helplines may be found via www.befrienders.org.