A booby-trap bomb found by police on north Belfast's Antrim Road last month was attached to a child's bicycle, it has been revealed.
The bomb was the second found in the area during a security operation which lasted a number of days.
Police believe they were lured to where the first bomb was found after a window was smashed in a video shop.
Three men - all of them aged in their 30s - have been arrested and are being questioned about the attempted attack.
Detectives have released images of the bike and of a man at the video store close to the first bomb's location.
Although neither bomb exploded, the senior investigating detective said a trap had been put in place "to kill police officers which could easily have murdered members of the public".
Police were first called to the Xtra-Vision shop on the Antrim Road on the night of Sunday 23 January after a man damaged a window and ran off.
On the following Tuesday, following a number of anonymous warnings, officers discovered a bomb close to the shop.
"Detectives from Serious Crime Branch are following one line of enquiry that the incident of criminal damage at Xtra-Vision and the bomb alert may be connected," Detective Chief Inspector Justyn Galloway said.
The second device attached to the child's bike was found beside a scout hut two days later.
"We are releasing footage of the man who was seen in the vicinity of the Xtra-Vision store.
"This man may have information which is vital to the investigation. Do you know who he is? If so please contact police," Det Ins Galloway said.
"We are also releasing a photograph of the child's bicycle which was used to disguise the booby-trap device.
"The bicycle is quite distinctive, and our second appeal is to anyone whose child has owned such a bike and lost it or had it stolen, or anyone who has sold a bicycle similar to this privately," he said.
Anyone with information is asked to contact detectives at North Queen Street Police Station on 02890 561804 or Crimestoppers on 0800 555 111.
About 50 families were moved from their homes during the security operation.