The death of a woman killed after her former partner forced his way into a house in Bristol with explosives is to be investigated by the police watchdog.

Jo Shaw, 35, sustained fatal injuries in the blast in the Frenchay area of the city on 3 May. Her former partner Ryan Kelly, 41, was also killed in the explosion.

The Independent Office for Police Conduct said it was investigating the contact Shaw and Kelly had with Avon and Somerset police. Police last had contact with Shaw four days before the explosion and the investigation will look at incidents over a five-year period from May 2021. Kelly had been accused of stalking, harassment and assault.

The IOPC engagement director Derrick Campbell said: “My thoughts and sympathies are with everyone affected at this very difficult time.

“We are independent of the police and it is important that we carry out a thorough investigation, to fully establish the circumstances of what happened prior to the tragic events.

“There is a significant history of police involvement in relation to Mr Kelly’s behaviour, including allegations of stalking, harassment and assault which we need to examine as part of our investigation.

“We are reviewing extensive documentation detailing that history as part of our inquiries. We will be keeping all interested parties updated as our investigation, which is at an early stage, progresses.”

Avon and Somerset police are treating the cause of the explosion as deliberate and recorded Shaw’s death as a homicide. The force is not looking for anyone else in connection with her death.

Three other people, including a child, sustained minor injuries.

Avon coroner’s court has heard that Shaw died from a “penetrating fragmentation blast injury to the chest and pelvis”, while Kelly sustained “blast injuries to head, neck, torso and limbs”.

Police previously said a call was received from a person inside the house at 6.17am reporting a domestic-related incident, saying a man they knew had forced entry to the house.

The caller remained on the line while officers were dispatched and at 6.30am the caller told police the man was believed to be in possession of an explosive device.

About two minutes later there was an explosion at the property, in which Shaw and Kelly died.

Officers arrived at the property at 6.34am and fire and ambulance services shortly afterwards.

A major incident was declared after the explosion and officers worked with Bristol city council to evacuate neighbours and set up a rest centre.

Searches were carried out by an army explosive ordnance disposal team and specialist police officers.

Searches also took place at an address where Kelly lived. No evacuations were required there.