The 31-year-old suspect in the Killamarsh murders was taken to hospital to be treated for self-inflicted minor injuries, the police have said.
He is now in police custody, following his arrest at the property where four people were found dead in Derbyshire.
An online portal has been set up for people to submit videos and dashcam footage of the incident.
Terri Harris, 35, died along with her young daughter Lacey Bennett, 11, and son John Paul Bennett, 13. Lacey’s friend Connie Gent, 11, who had been staying that evening for a sleepover, was also found dead at the house on Chandos Crescent, Killamarsh, on Sunday.
Connie’s heartbroken father, Charlie Gent, said he “can’t even put into words” how he is feeling. He said he didn’t want “anyone to ever go through what I am going through right now”.
Speaking in a post on social media, Mr Gent said: “Parents spend as much time with your kids as you possibly can. If you’re a parent and arguing please don’t stop that child from seeing the other parent.
“You never know what’s round the corner.”
Speaking at the scene of the incident, Lacey and John Paul’s grandmother, Dianne Bennett, 63, told The Independent that she wants justice for her family.
Referring to the perpetrator, she said: “I’ll be going to the trial and I’ll be looking him in the eyes.”
She added: “I worry about all my grandkids when they get older. I’m just worrying about Jason. He’s a lovely lad, so jolly, but you can’t help breakups can you.”
Jason Bennett, dad to Lacey and John Paul, visited the scene on Monday and said: “I’m broken, I just want to kiss my babies.”
A fundraising page set up on GoFundMe for the families of the victims has now raised more than £14,000.
The authorities were called to the scene at 7.30am on Sunday amid concerns for a man – understood to be the now-arrested suspect – before finding the four victims.
They have said that this is an isolated incident and they are not looking for anyone else in relation to the deaths.
The children’s school, Outwood Academy City in Sheffield, paid tribute to their pupils in a statement on Tuesday.
It read: “We are all devastated at the loss of three of our students; John Bennett, Lacey Bennett and Connie Gent.
“Our hearts are broken after this tragic news, and we would like to offer our deepest sympathies and condolences on behalf of everyone at Outwood Academy City to the families of those affected.
“The children had bright futures ahead of them but sadly none of us will get to see this. The school community will remember them fondly.”
They described Lacey and Connie as making “a positive impact on everyone they came into contact with” and John as a “popular and polite young man, well-liked by staff and with a close-knit group of friends”.
Detective Chief Inspector, Sally Blaiklock, who is leading the investigation said: “Our thoughts remain with the families of Terri, John Paul, Lacey and Connie – as well as the communities that have been affected by this most tragic of incidents.
“A large scene remains in place on Chandos Crescent and local residents will see an increased police presence in the area over the coming days, including patrols by officers in the local area.
“I would urge anyone who is concerned about the incident to speak to officers in the area or use the online reporting tool to pass information in confidence.
“Myself and the team of detectives are particularly keen to hear from anyone who was in Chandos Crescent between 6pm on Saturday 18 September and 7am on Sunday 19 September, as well as anyone who may have video footage of the street.
“That can include dashcam, mobile phone footage, CCTV or video doorbells.”