ITV News UK Editor Paul Brand looks into the gunman's background
Jake Davison, the shooter who killed five people in Plymouth before turning the gun on himself, appeared to have an interest in the 'incel' culture, short for 'involuntary celibate'.
Although the 22-year-old said he would not call himself an incel, he had researched them online and spoke about them as "people similar to me have had nothing but themselves".
The misogynistic incel culture has amassed a following online among some men who feel angry and resentful as they believe women do not find them attractive.
The gunman had posted on the popular forum Reddit nine months ago, posing the question , "Am I ugly? Brutally honest", as he asked users to give him their opinions. Whatever their answers, his state of mind was not improved in later postings.
In one video, posted on 28 July, he said he did not have “any willpower to do anything anymore” and discussed the misogynistic ‘incel’ movement.
The 22-year-old, who worked as an apprentice at Babcock International since August 2020, “liked” a series of clips about guns and shared posts on social media quoting former US president Donald Trump as well as pictures of a statue holding a rifle.
He had also written about mass shootings, saying they were a new phenonema that cannot be blamed on guns.
Former chief crown prosecutor for the North West Nazir Afzal told BBC Breakfast on Saturday there were 10,000 people with incel views like Davison in the country.
Lewis Brace at Exeter University has studied the incel culture and says it can have tragic consequences.
He told ITV News: "In most people, this materialises in severe cases of depression and increase risk of suicide. But for a small minority, these views start to express themselves in violent ways and they start to think about violent actions against women."
Elliot Rodger, 22, was probably the best known incel killer. Seven years ago in California, he shot dead six people and injured many more before turning his gun on himself.
Speaking about the threat of incels, Mr Afzal said: "How many of them, a small minority, are a threat?"
He continued: “We have now seen posts on various social media sites which paint a picture of somebody that has a very low opinion or had a very low opinion of women, who seemed to have a belief he was entitled to do whatever he wanted to, a real expectation that women were some kind of lesser being.
“That kind of extreme misogyny of the type we have seen here and in terms of the incel community is a threat to all women and, ultimately, to all our communities.”
He said the government could consider treating incels as terrorists if there are more attacks like the Plymouth shootings. It means authorities would have more powers to investigate it.
But Sir Peter Fahy, former chief constable of Greater Manchester Police, argued on the same TV programme that partners and ex-partners were more of a risk to women than incels.
Davison killed his 51-year-old mother Maxine Davison, also known as Maxine Chapman, at a house in Biddick Drive, Keyham, on Thursday evening.
He then killed Sophie Martyn, aged three, and her father Lee Martyn, aged 43, in the street.
He killed Stephen Washington, 59, in a nearby park, before shooting Kate Shepherd, 66, on Henderson Place. Ms Shepherd later died at Derriford Hospital.
Davison also shot two residents – a man aged 33 and a 53-year-old woman, who are known to each other – in Biddick Drive. They have significant, though not life-threatening, injuries.