Detectives investigating the "sickening" murder of an innocent 14-year-old schoolgirl were last night questioning a suspect in connection with the shooting.

Officers made an arrest following the death of Danielle Beccan, who was gunned down just yards from her Nottingham home as she returned from a fairground with friends on Saturday.

But police said they were still baffled as to why the youngster, or her group of friends, might have been targeted by gunmen in the early hours of the morning.

Nottinghamshire Police Assistant Chief Constable Sue Fish said last night: "She was an innocent 14-year-old girl and I think we have to concentrate on the fact that this was a child who has been senselessly shot and killed."

Heartbroken friends and family members last night continued to leave messages and flowers at the spot where Danielle was killed.

A message from the her mother, Paula Platt, attached to a toy dog, read: "We will miss you always. Our hearts are broken."

Her grandfather, Alvin, was tearful as he spoke of his "friendly, easy-going" granddaughter and how his family had been devastated by the drive-by shooting.

Police said they had spoken to some of Danielle's friends and believed another group of about 30 youngsters were in the area at the time and could help to trace the killers.

Ms Fish said: "We want to trace people in another group just a few hundred yards away from where she was shot. It is a very strong possibility that these people were witnesses.

"People are very shocked and revolted by this appalling crime. It is a terrible and sickening crime.

"We need to know the motive. We need to know whether it was a case of mistaken identity."

Superintendent Dave Colbeck said officers had received intelligence that there could be some trouble at the annual Goose Fair and measures were put in place to combat any problems.

However, he said the information was not specific and did not lead to any extra patrols in the suburb of St Ann's, where Danielle was killed.

He said: "We have not had a gun-related injury in Nottingham for four months. We have made huge inroads into dealing with gun crime in Nottingham."

But he said: "There is still a core of individuals who believe the only way they can build their business is by using firearms."

A post-mortem examination showed Danielle died from a gunshot wound to the abdomen.

Nottingham East MP John Heppell later branded Danielle's killers "cowardly".

He said: "There is no evidence of any links with any gangs, any drugs, anything of that sort.

"It leads us to the conclusion that this is some sort of indiscriminate killing. It is a cold-blooded killing."