LONDON - The half-brother of England and Tottenham Hotspur striker Jermain Defoe has died after being attacked on a London street, police sources said on Saturday. A murder investigation was launched after Jade Defoe, 26, died in hospital on Friday from head injuries sustained earlier in the week. "We do not believe a weapon was used during the assault," police said in a statement. "We retain an open mind as to any motive and inquiries continue to establish the full circumstances of the incident." Media reports said Defoe did not travel with his team mates for Saturday's Premier League match against Manchester United.