Detectives investigating the explosive device found in Lisburn on Saturday July 30 revisited the area at the weekend, one week after the incident occurred.
Detectives spoke to pedestrians in the Market Place area to see if they were in the vicinity at the same time last week and saw anything which may have been suspicious.
At the time of the incident, police said they believed the device may have fallen from a vehicle.
Follow up searches were later carried out in the Lagmore area of West Belfast and a vehicle was seized for further investigation.
Detectives have also issued an appeal for the drivers of four particular vehicles - a grey-coloured BMW X3 or X5, a blue-coloured Ford Focus, a grey-coloured Vauxhall Astra, and a silver-coloured Suzuki jeep - to come forward and speak to the police as soon as possible.
Speaking ahead of the visit to the scene last Saturday (August 6), Detective Chief Inspector Alison Rowland, from Serious Crime Branch, explained: “Earlier this week we issued an appeal to speak to the drivers of a number of vehicles who we know were in the area last Saturday and the response was positive.
“I am hoping that by talking to pedestrians in the area today, we may be get further information that can assist the investigation.
“I would appeal once again to anyone who was in the Market Place area on Saturday 30 July at around 2pm to contact us.”
Detectives can be reached by calling the non-emergency number 101 and asking for the Lisburn bomb enquiry team.
Alternatively, if people would prefer to provide information without giving their details, they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.