"We could recover 4.5 kg of the gold from the accused's possession," said Atulchandra Kulkarni, joint commissioner of police (crime).
Complainant Pramod Mehta, who runs a jewelry firm in south Mumbai, had taken the taxi driven by Laxman Navik (29) on his way back to his house in suburban Ghatkopar on May 2.
"During the journey, Navik overheard Mehta's phone conversation and learnt that Mehta was carrying a big quantity of gold with him," said Kulkarni.
After Mehta got out of the taxi and was paying the fare, Navik drove off with the bag containing the gold in the taxi, leaving a helpless Mehta behind, the JCP said.
After questioning, Navik confessed to the crime, Kulkarni said. The taxi too was seized.
Navik, who hails from Uttar Pradesh, would be produced before the court tomorrow.