A police force is being probed following a fatal 'grenade' explosion that killed a mother and her abusive gangster ex-boyfriend.

Jo Shaw, 35, was killed on May 3 by her violent ex-boyfriend Ryan Kelly, 41, in a suspected murder-suicide after he forced his way into her home in Bristol and detonated an explosive device.

The brave mother-of-one was able to save her child's life in the moments before the explosion by sending him outside to play on a trampoline after a serious argument began between her and Kelly. 

It has been reported that Ms Shaw repeatedly called police over Kelly's behaviour, who also stalked and assaulted Ms Shaw. 

Now, the Independent Office for Police Conduct (IOPC) has said it was investigating the contact Ms Shaw and Mr Kelly had with Avon and Somerset Police prior to their deaths.

The watchdog said police last had contact with Ms Shaw four days before the explosion and the investigation would look at past incidents over a five-year period, from May 2021.

IOPC 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 of May 3.

'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 Ms 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.

Separate opening inquests heard Ms Shaw died from a 'penetrating fragmentation blast injury to the chest and pelvis', while Kelly suffered 'blast injuries to head, neck, torso and limbs'.

Inquests are due to resume in August at Avon Coroner's Court.

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 to the house. 

At 6.30am the caller told police the man was believed to be in possession of an explosive device and two minutes later there was an explosion at the property, in which Ms Shaw and Kelly died.

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

Residents in neighbouring properties were evacuated as a precaution and searches were carried out by the Army to ensure the area was safe.

Searches also took place at an address in the Speedwell area of the city where Mr Kelly lived. No evacuations were required at that location.

Following her tragic death, loving tributes poured in for Ms Shaw, with her heartbroken family paying homage to her 'warmth, kindness, and strength'.

A close friend also revealed that the mother had a love of poetry and shared some of her tender lyrics in which she evokes her 'unbreakable, precious thread' with her family.

The poem, published on a GoFundMe page set up to raise money for Ms Shaw's funeral and funds for her only child, read: 'Although it isn't visible, we always know it's there. Our bond cannot be broken; our souls will never part. My family's always with me, no matter where we are.'

Josie Quinn, who set up the fundraiser, said her 'beautiful friend' was 'one of the most caring and selfless people anyone could have known'.

She said: 'She always put others before herself and brought light, warmth, and kindness to everyone around her.

'Her child was her entire world. Anyone who knew Jo knew she would have done anything to protect them.

'No child should ever have to experience such a loss. Their world has been turned upside down, losing the person who loved them unconditionally, who made them feel safe, and who was always there for them.'

Ms Quinn also revealed that Ms Shaw's family had been left devastated by the explosion.

The GoFundMe has so far raised more than £24,000 of its £35,000.

Ms Shaw, known as Jo, grew up in the Stapleton area of Bristol where her family said she was well-known for her 'bubbly, friendly personality'.

They said she loved meeting new people, listening to their stories, sharing advice and forming connections resulting in 'eternal friendships'.

She was the 'life and soul not only of the party, but our lives', they added.