Detectives have warned innocent people would have been killed if a 400lb bomb had exploded in Belfast last weekend.
Members of the PSNI's Serious Crime Branch revisited the scene of the failed bomb attack on Saturday night outside the headquarters of the Policing Board to appeal for information.
Senior Investigating Officer, Detective Chief Inspector Debbie McMaster, said her team were making a number of inquiries, in particular about two vehicles involved.
The bomb partially exploded after a black Mazda broke through a barrier of the complex last Saturday night.
Nobody was hurt in the attack, but two men were seen escaping from the area at Clarendon Dock.
"Had this bomb fully exploded it would have killed and injured passers by and many buildings in the area would have been extensively damaged," said the Detective Chief Inspector.
"It was in the black Mazda 6 car.
"A red Nissan Primera car with the false registration number M83 EEC was discovered on fire in the New Lodge area of Belfast a short time after the incident at Clarendon Dock and it is believed at this stage to be linked."
Police have released pictures of cars similar to those suspected to have been used in the attack.
A leaflet was also being handed out to members of the public.
Police appealed for anyone who saw these cars travelling close to each other in the greater Belfast area prior to the attack last Saturday to contact them.
"We would also like to speak to anyone who saw the Nissan Primera car being abandoned and set alight in the New Lodge area the same night," added the senior officer.
© Press Association