A man is under arrest after a Facebook page was set up lauding suspected police officer double killer Dale Cregan as a "legend".
The "tribute" went online within hours of PCs Nicola Hughes, 23, and Fiona Bone, 32, dying in a gun and grenade attack in Hattersley, Tameside, on Tuesday morning.
Greater Manchester Police announced the arrest as officers continued to question Cregan, 29, on suspicion of murder.
He was detained after walking into a nearby police station after the attack.
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Kevin Davis, 53, ran a medical company and helped to treat a 15-year-old who had taken a drugs overdose despite not having qualifications.
CCTV shows the 19-year-old victim being struck by a car and thrown metres into the air, before he lands on the pavement and slides along it.
Police are investigating a fresh allegation against John Worboys alleged to have taken place in 1997, ITV News understands.