GARDAÍ have identified four suspects from the same family who they believe ordered the gangland murder of Stephen 'Madser' Byrne, it is understood.

Byrne (32) was shot dead by a gunman on a bicycle as he stood talking to three people at the junction of Sherriff Street and St Laurence's Place East in Dublin in broad daylight on Tuesday afternoon. Byrne was the prime suspect for the murder more than three years ago of Stephen Ledden in his parents' home at Oriel Street. A close relative of his was the intended target and Ledden's death was a case of mistaken identity. Following this murder, several people swore revenge against Byrne.

Byrne, a convicted criminal, is the fifth victim of the Sheriff Street feud involving former friends, who split after a notorious gangster, Christy Griffin, was arrested for the rape of his partner's daughter.

Griffin was subsequently convicted of the crime and jailed for life. Byrne and several other members of the once close-knit crime gang turned against Griffin and supported the young girl's family. Others, including associates of Ledden, sided with Griffin.

Byrne is one of three first cousins who have been murdered in the bloody feud – Gerard 'Batt' Byrne (25) was shot dead in 2006 and Aiden Byrne (32) was shot dead in February. Stephen Byrne's brother David (26) died last July after being hit over the head with a sock filled with batteries while imprisoned in Mountjoy. His body was then desecrated by people who broke into the funeral home and wrote the word "Rats" across his forehead.

The accidental murder of Stephen Ledden by the latest murder victim was retaliation for the killing of Gerard 'Batt' Byrne.

The three young men standing on the corner when the 32-year-old was shot dead have all been arrested in relation to withholding information.

One man in his 20s and two boys, aged 15 and 16, have all been questioned and released. Two other men are now in custody.

Byrne is believed to have left his home, off Sheriff Street, to meet someone when he was shot dead.

Detectives are not yet close to making any other arrests in relation to the murder probe. Byrne had been made aware his life was in direct danger and was "living in fear of getting shot".

A source said that officers were working hard behind the scenes in Sherriff Street to try and ensure there were no retaliations for the latest murder.

Byrne's mother Margaret last week called for an end to the violence as she prepared to bury her second son.

"He was my son and I loved him... no matter what," she said. "He was sitting in the house with me when he said he was going down to the corner to meet friends. He knew his life was in danger but he still went out. He was afraid... five minutes later he was dead."