June 13 [12:00 EDT] -- Trouble continues to congregate around British R&B star Mark Morrison, whose "Return of the Mack" single has been a mainstay on the top ten chart for several weeks.

Morrison is currently imprisoned in London, serving three months for threatening a policeman with a stun gun last fall. Still another conviction, this one for assaulting a man in London and damaging his car, resulted in a three-week concurrent term being added to his rap sheet.

Now, the singer has had a two-week concurrent term tacked on, this one for smashing a photographer's camera outside a London hotel last summer.

Since each of these additional sentences is concurrent, Morrison won't be serving any extra time, but the convictions could make it difficult for the performer to ever obtain a visa and perform in this country.

In the meantime, the singer's lawyer says he's been threatened by so many inmates that prison officials have moved him into a hospital wing.