Neighbours spotted the men near Judge Nazim Khoury's car overnight and reported them to security forces on Saturday, a security source said.
The men dumped the explosives and wires and fled after the neighbours raised the alarm, the source added.
Security forces were searching the Sahil Alma area where the explosives were found.
A series of bombings and assassinations has rocked Lebanon since the 14 February killing of former prime minister Rafiq al-Hariri threw the country into its worst political crisis since the 1975-1990 civil war.
The attacks have largely targeted Christian politicians and journalists critical of neighbouring Syria's role in Lebanon. The latest bombing seriously wounded an anti-Syrian television news anchor on Sunday.
Khoury is leading investigations into possible money-laundering at Banque al-Madina, which is being liquidated by the central bank after it fell into financial difficulties.