A 13-year-old boy has been charged with murder, Scotland Yard said.
Police are investigating the murder of Martin Thomas, 39, who was pronounced dead at his home in Huntingfield Road, Roehampton, south west London.
The teenager, who cannot be named because of his age, has been remanded in custody to appear at Wimbledon Magistrates' Court on Monday.
Police continue to appeal for information surrounding the murder on April 22, particularly information that would assist detectives in identifying three people seen in the area prior to the incident.
A post-mortem gave cause of death as haemorrhaging due to a stab wound to the lung, police said.
Next of kin have been informed.
Detective Chief Inspector Charlie King, from the Homicide and Major Crime Command, said earlier: "At this early stage we are keeping an open mind about any possible motive.
"Members of the public have already provided us with accounts of three young men seen loitering in the area prior to the incident. I am directly appealing to these young men to come forward and speak us.
"I am also urging anyone who may have more information regarding this incident to contact us."
A 15-year-old boy has already appeared in court charged with murder and has been remanded in custody.
A 17-year-old and a 16-year-old both arrested on suspicion of murder have been released on bail.