The force's Homicide and Major Enquiry Team have arrested and charged a man and a woman in connection with the death of Sebastian Kalinowski, but want to speak to anyone who knew him or has information about him to get in touch with them.
Sebastian, who is originally from Poland, is said to have only been in the UK for a short time before his death, spoke little English and had limited social contacts with people.
Police were called to a house on Leeds Road in Huddersfield on August 13 by the ambulance service and Sebastian was found unconscious. He was given medical treatment but died later.
Examinations showed he had a number of physical injuries and, a result of enquiries, officers arrested Agnieszka Kalinowska, 34, and Andrezej Latoszewski, 37, both of Leeds Road Huddersfield. They were due in front of magistrates in Leeds today.
Detective Chief Inspector Tony Nicholson said: “We are continuing to develop a number of enquiries into the death of Sebastian and this is very much a murder investigation.
“As a man and woman have been charged we are limited in what we can say to ensure the integrity of the court process, but I am very much appealing for information about Sebastian to help us build a picture of him, his movements and lifestyle
“We are in contact with his family in Poland and know he had only been in England for a short amount of time and spoke limited English.
“He was enrolled at North Huddersfield Trust School at Fartown school and I would appreciate information from anyone who perhaps knew him at school and can tell us more about him.
“Anyone who can assist our enquiries or has information about Sebastian’s murder is asked to contact the Homicide and Major Enquiry Team on 101 referencing crime number 13210409705.
“information can also be given online at www.westyorkshire.police.uk/101livechat or anonymously to the independent Crimestoppers charity on 0800 555 111."