Police today confirmed that two men — one in his teens and the other in his early 20s — had gone to Strand Road police station after the PSNI carried out a number of searches in the city yesterday.

The men were today being questioned at Antrim Custody Suite. A PSNI spokeswoman confirmed the two men had been arrested but said they were also seeking a number of other men, who were also urged to hand themselves in.

The arrests came as the local community sent a defiant message that it will not bow down to the cold-blooded killers of a pizza delivery man who stood up to them.

Dissident republicans are believed to be behind the murder of the young dad-to-be in the early hours of yesterday.

As over 1,000 people took to the streets in solidarity with Mr Shiels' family, the INLA denied speculation that its members were involved in the Creggan killing.

Mr Shiels was gunned down around 12.45am at Eastway, as he confronted masked men who were challenging a group of young people.

Deputy First Minister Martin McGuinness told the killers at the vigil: " Do yourselves a favour, do us a favour, do the community you profess to defend a favour. Please go away."

Mr McGuinness said today that many people have given statements to the police and should be proud of the way they stood up for their community.

He also told the killers' families that the community was up in arms at the murder and that if parents or other relatives had information, they should go to the police.

The murdered man's family said his death came at a time when he was proudly waiting for the arrival of his first child.

Mr Shiels' adoptive sister, Maureen Wilkinson, said that the boy was due to arrive any day, having been expected last Saturday

The family also today spoke of their "deep sorrow" after joining hundreds of local people at the vigil held in his memory.

They said they were finding it difficult to come to terms with the " terrible tragedy which has been visited upon our family".

They also said they hoped Emmett's killers would be made accountable for their actions.

The family's statement read: "The sad reality is that this death should not have occurred. This was not a case of mistaken identity but a deliberate act and we are calling on anyone with any information to bring it forward so that those who carried this out this murder are held responsible. We are heartened by the great support of our friends."