On Facebook, Anand Shah has uploaded photos of his son, Karnit, along with his phone number - he hopes a stranger somewhere will respond with information that could help him locate Karnit.
"Whoever has him, I pray they are taking care of him. With folded hands, I appeal to them, please don't hurt my son" says Anand, his voice unsteady.
On Wednesday last week, Karnit was playing downstairs near the apartment building where the Shahs have lived for nearly a year in the suburb of Kandivii. Anand, a stockbroker, is married to Alpa, a housewife. Their older child, a daughter, is in Class 4.
The Shahs say they have no personal or professional rivalries that may have prompted the kidnapping of their young son.
The police says that children they have questioned in the neighbourhood have spoken of a "Sunny Uncle", possibly in his 20s, who has been seen lately offering chocolates and sweets to them. A police sketch has been prepared on the basis of their descriptions.
The police has set up five teams to try and locate Karnit. There has been no ransom call for him. On Facebook, thousands of people have forwarded Karnit's photos, but so far, no clue has emerged.
The Shahs are offering two lakhs as a reward for any information that could help them locate Karnit.
They have this description of Karnit. "He is fair, 3.5 feet tall, and was last seen wearing an orange t-shirt and blue denim shorts. He can speak Gujarati and Hindi and knows his address and his father's cell number. If you spot him - please call 9867023992 or 9821818626."