Three teenagers are still being questioned in relation to the murder of David Byrne in Inchicore, Dublin, on Saturday.
Six boys and one girl ranging in age from 13 to 17 years were arrested by gardaí on Tuesday in a series of operations when gardaí called to a number of houses in Drimnagh.
Some of those held were being questioned in direct connection with the murder while others were held on suspicion of witholding information.
A further arrest was made last nigth with the arrest of a second girl. She is still being held along with the first girl and a boy while the other suspects have all been released without charge.
The postmortem on the remains of the deceased, a 19-year-old with an address in Drimnagh, southwest Dublin, revealed he was stabbed in the back several times and suffered damage to his kidneys.
Gardaí believe Mr Byrne came out of his home at the Davitt House complex on Davitt Road, Drimnagh, just after 10pm on Saturday.
He was chased by a gang of at least four across a bridge over the Grand Canal and into the nearby Emmet Court residential complex in Inchicore.
At least one of the gang caught up with Mr Byrne in the cul-de-sac car park and courtyard in Emmet Court and stabbed him as his three accomplices kept lookout.
The gang then fled on foot. A local resident rang gardaí and when uniformed members and paramedics arrived at the scene just before 10.30pm Mr Byrne was still alive.
He was taken by ambulance to St James's Hospital but was pronounced dead there at 11.45pm. A murder investigation was immediately begun.
Divers from the Garda Water Unit searched the Grand Canal close to where the murder happened and on Sunday found a number of knives in the water.
The knives are being examined in an effort to determine if any of them is the murder weapon.
Mr Byrne was known to gardaí and had been involved in a number of assaults. He had been known to sometimes carry a knife. Gardaí believe he was involved in the drugs trade at a minor level.
Gardaí are trying to determine if the teenagers who fatally attacked him are linked to a gang of older drug dealers that has been involved in a gangland feud between two gangs in Crumlin and Drimnagh for over a decade.
However, gardaí are now investigating if the killing was part of a personal dispute rather than a row over a drugs debt as initially believed.
They also believe the attacker may have intended to injure David Byrne rather than kill him.