The two cases happened in the early hours Cambridge Road and Burnaby Road.
Teenager Arrested After Boy Robbed
A teenager has been arrested on suspicion of robbing a 14-year-old boy in a park in Portsmouth.
He was approached and threatened with violence by another youth in a play park area of Church Road around 3pm on Saturday 30 March - a Blackberry Curve mobile phone was reported stolen.
A 15-year-old boy was arrested during the early hours of Monday 1 April on suspicion of robbery. He was questioned and later bailed until May 3 while investigations continue.
Detective Constable Pete Bambury said: "This was a robbery in the middle of a residential part of Portsmouth during the afternoon. I am appealing to any members of the local community, who may have seen what happened to the boy and in turn speak to the police."
Anyone with information is asked to contact CID at Fratton Police Station by phoning 101.
Lewis Hine - who has a brain tumour - posted an inspirational film about his life, on his 16th birthday last week.
One of the men's targets was Ernest Jones in Portsmouth, taking £57,000 worth of watches.
Detectives Searching For Dash Cam Footage Around Gilpin Close.
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