The police watchdog is to investigate after the death of 43-year-old Matthew Boorman in a series of stabbings near Tewkesbury in Gloucestershire.
Another man was also injured in the incident and is in hospital with serious injuries.
Two men and a woman were attacked on the Wheatpieces estate in Walton Cardiff on the evening of Tuesday 5 October 2021.
A man in his 50s has been arrested by police in connection with the stabbings.
The incident has been referred to the Independent Office for Police Conduct (IOPC) due to the force having had prior contact with the suspect and victim.
In a statement, Mr Boorman's family said: "Matthew was a loving husband and a father to three gorgeous young children who all love him and miss him tremendously.
"He was an uncle, a brother and a son. It broke our hearts to lose him too soon."
Chief Insp Roddy Gosden speaks about 'horrific' incident
Chief Insp Gosden from the force said: "This was a horrific incident in a quiet residential area. We understand those who saw what happened will be traumatised and many in the local community will be upset and worried.
"Today and over the next few days local policing team officers will be patrolling the area to listen to people’s concerns, refer people to available support and provide reassurance.
"The man who was arrested in connection with the incident remains in police custody at this time and we can confirm we’re not seeking anyone else in connection with our enquiries.
"Our thanks to those who were first at the scene, including two off-duty police officers, who bravely intervened to tackle and restrain the suspect.
"Our thoughts at this time are with the family of the man who died and those who were injured. The next of kin are currently receiving support from our family liaison officers."
Ch Insp Gosden issued the following plea: "The investigation continues and anyone who has not already spoken to us, or anyone who has video footage of the incident, is asked to please contact us and not to post it on social media.
"Due to previous police contact with the suspect and victim the Constabulary is referring itself to the Independent Office for Police Conduct," Ch Insp Gosden added.
"This is standard practice in such circumstances. In light of this and our ongoing investigation it would not be appropriate to comment further on the details of the case."
Police would like to hear from anyone with information who has not yet come forward - as well as anyone with mobile phone footage.
They can call 101 quoting incident 320 of 5 October or filling in an online form.