British rapper Dappy has apologised to the the widow of a murdered teacher after name-checking his killer in a new music video.
The N-Dubz star has come under fire for including the message 'Free Leo Chindamo' in the opening credits of the promo for his new single Tarzan 2.
Chindamo was just 15 years old when he stabbed Philip Lawrence outside a London school in 1995 after the principal stepped in to stop a fight.
Dappy went to the same school as Chindamo, who was released in 2010 after 12 years behind bars but was sent back to jail just four months later.
Lawrence's outraged relatives have accused Dappy - real name Costadinos Contostavlos - of profiting off their pain.
His widow Frances tells Britain's The Sun, "I haven't heard the song yet. But I don't think it is right someone should be making money from using his name in a song."
However, the hip-hop star is adamant he meant no offence with his tribute to Chindamo.
Taking to Twitter.com to apologise, he writes, "Just wanted to say I honestly wasn't aware he did that, I knew his brother from when I was young.
"In no way did I intend to cause any upset and certainly didn't know about his past. My heart goes out to Mr Laurence's (sic) family and I know the pain of losing a loved one, sincerely Daps."