The 43-year-old former senior Continuity IRA figure was gunned down in broad daylight in the Peter Pan complex on the Springfield Road at 4.45pm.A 26-year-old man has been arrested in west Belfast by police investigating the murder and is being questioned at Antrim Serious Crime Suite.Police on Saturday revealed that Tommy Crossan was working at the fuel depot business of a family friend, sitting in a portable cabin office when he was shot through the window a number of times at close range.He was hit in the upper body and pronounced dead at the scene.Officers said Mr Crossan - who is from west Belfast and leaves behind a wife, six children and five grandchildren - was known to police and they have not ruled out a dissident republican feud in relation to his murder.Senior Investigating Officer Detective Superintendent Jonathan Roberts said nothing justifies this "ruthless" and "brutal" attack.One line of enquiry centres on individuals or groups who would associate themselves with dissident groupings, however we are keeping an open mind.Detective Superintendent Jonathan RobertsHe continued: "The murder of Mr Crossan on the Springfield Road yesterday was a brutal and ruthless attack which has no place in society."Mr Crossan was known to police but no matter what his lifestyle was, absolutely nothing justifies this barbaric action against him. Police are working on a number of lines of enquiry."Relatives and a large crowd of onlookers gathered at the scene of the murder investigation as officers cordoned off the area on Good Friday.Forensics teams are still investigating the scene of the killing however the Lower Springfield Road has now reopened.A red BMW car, which was set on fire at nearby Beechmount Grove, was discovered after the fatal shooting and a link is being investigated.Detective Superintendent Jonathan Roberts said: "A red coloured BMW, believed to be linked to the murder, was found burned out a short time later in the Beechmount Grove area of the city."It has not been reported as stolen to the police, however there have been a number of sightings of the vehicle in the area over recent weeks."We are particularly appealing for anyone who may have witnessed the red coloured BMW car, registration number OEZ 9177, which was seen leaving the area around the time of the murder or anyone who may have seen it in the Beechmount Grove area later on."There has been widespread political condemnation following the murder, led by the First and deputy First Ministers who have issued a joint statement.Peter Robinson, DUP, said: "The small minority of people who want to continue terrorising the community need to understand that they will not be allowed to drag Northern Ireland back to the dark days of the past. They must be hunted down and brought to justice."Martin McGuinness, Sinn Féin, said: "The people behind this killing are criminals and will further no cause through this shooting. The peace process is rock solid and all right thinking people across the community oppose and reject the actions of the people behind this murder."Police said they have set up an incident room for the murder and appealed for information.Detective Superintendent Jonathan Roberts added: "Those responsible for this ruthless murder will only be brought before the courts and put behind bars if people with information work with police."Members of the public can contact the special incident room on 02890 259542.