Three children killed during a sleepover in Derbyshire were “popular” and “positive” pupils who had bright futures ahead of them, their school has said, as police continued to question a man on suspicion of murder. Terri Harris, 35, was killed along with her children, John Paul Bennett, 13, Lacey Bennett, 11, and Lacey’s friend Connie Gent, 11, who was staying at their house at the weekend. A 31-year-old man was arrested at the semi-detached house in Killamarsh, on suspicion of all four murders shortly after 7.25am on Sunday. Police said the man was taken to hospital with “self-inflicted minor injuries” but remained in custody for questioning. The three children were all pupils at Outwood Academy City in Sheffield, which said it was “devastated” by their loss. In a statement on Tuesday, the school said: “Our hearts are broken after this weekend’s 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. Lacey and Connie had just embarked on their secondary school journey with us and already made a positive impression on everyone they came into contact with. “John Paul was a popular and polite young man, well liked by staff and with a close-knit group of friends. It is difficult to process the news, but the memories we have of John Paul, Lacey and Connie will live on for ever at the school.” Jason Bennett, the father of John Paul and Lacey, collapsed in tears as he laid flowers at the police cordon around the property on Monday morning. Asked about his feelings as he left, he told reporters: “Heart broken, million pieces, shattered.” Charlie Gent, the father of Connie, wrote on social media: “My little girl has gone, I can’t even put into words or even how to feel or react right now. “I shouldn’t even be writing this, now I have to live with the fact I was helpless to protect her as I always promised and she’s gone.” Outwood Academy City, five miles north-west of the Bennetts’ home, was closed on Monday as a mark of respect to the families. The school is offering specialist support to all pupils and staff. It said: “We will remember John Paul, Lacey and Connie fondly and the significant contributions they made to Outwood Academy City in their time with us. “Our community is hurting right now, but as we often say, we are a family at Outwood Academy City and we will be doing everything that we can to support our students, staff and families during this traumatic time.” Detectives have appealed for witnesses to contact police, including anyone with footage of Chandos crescent between 6pm on Saturday and 7am on Sunday. DCI 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.”