CCTV of a gunman entering the home of a 27-year-old man who was shot dead in his bed is to be shown on the BBC's Crimewatch programme later.
Richard Deakin was shot in the chest at his home Meadway Street, Chasetown, in Staffordshire, on 5 July.
Staffordshire Police believe those responsible have links to the Wolverhampton, Tipton or Coseley areas in the Black Country.
The masked gunman can be seen in Mr Deakin's garden unwrapping a weapon.
Two men have been arrested and released on bail as part of the inquiry.
'Catch those responsible'
Mr Deakin moved to Chasetown with his fiance Megan in 2008 where they lived with their daughters, aged four and two.
He was alone at the time of his murder, police said.
Det Ch Insp Dave Garrett, who is leading the inquiry, said: "We are determined to catch those responsible for Richard's death and take them off the streets.
"Specially-trained officers are offering support to Richard's family at this tremendously difficult time.
"For their sake, it's crucial that we bring Richard's killers to justice. Somebody out there knows who murdered Richard.
"We hope that tonight's Crimewatch appeal will prompt them to do the decent thing and pick up the phone."
Crimewatch is on BBC1 at 2100 GMT