A fourth man has been charged with the murder of a man stabbed at his home.
Gambian national Tairu Jallow, 29, died after being attacked on Havelock Street, Kettering, on 14 January.
Kausu Ceesay, 23, from Birmingham, appeared at Northampton Magistrates' Court on Friday charged with murder. Three others have already been charged.
Meanwhile, Northamptonshire Police has released CCTV images of 10 people it believes could have information to help in the investigation.
The images are of individuals in Havelock Street between 20:30 and 21:30 GMT on the day of Mr Jallow's attack.
Three men - Babacarr Sylva, 31, from Nottingham, Ngange Sowe, 29, from Birmingham, and Clever Makande, 23, of Brandwood Crescent, Kings Norton, Birmingham - have also been charged with murder, alongside Mr Ceesay.
Det Insp Phil Mills said: "Although we have already charged four people, the investigation is still ongoing and we still need to speak to anyone who was in the area at the time of the murder.
"We have spoken to a number of witnesses but there are still more that we haven't been able to trace and who we believe may be able to help us.
"They may have seen or heard something that on its own appears insignificant but, when pieced together with other information, could be hugely important, and I urge them to call us."