- 28 people have been rescued so far while 7 injured are still in hospital
- Last night, Chief Minister Devendra Fadnavis visited the crash site
- Shiv Sena worker's nursing home on ground floor was being renovated
The police said the Siddhi Sai building was home to at least 12 families.
Former Congress corporator Pravin Chedda said the nursing home was run by Sunil Shitap and Swati Sunil Shitap.
"This hospital has been shut for the past two months. He (Sunil Shitap) wants to turn it into a guest house here...," Mr Chedda said.
Swati Sunil Shitap had contested and lost the last elections to the Brihanmumbai Municipal Corporation (BMC), earlier this year on a Shiv Sena ticket.
Maharashtra Chief Minister Devendra Fadnavis visited the accident site late last night and ordered an inquiry. Search and rescue operations are underway amid sporadic rain showers.
As local residents and Mr Rahangdale's team started the rescue effort, they were able to pull out around 28 people from under the debris over the next few hours. Two firemen were also injured during the operation.
Mumbai Mayor Mahadeshwar, who is also from the Shiv Sena promised that the guilty would not be spared.
"There will be a full investigation and whoever it may be, if he is guilty then there will be a strong action taken against him," he said.
There have been several instances of buildings collapsing during the monsoon. In many instances, the incident was linked to illegal construction or people staying in buildings despite being classified as dilapidated.
In August last year, eight people were killed after a portion of a two-storey building collapsed in Bhiwandi on the outskirts of Mumbai. In October, six children died after a five-storey building had collapsed in Mumbai's Bandra East,
A dilapidated building killed 12 people when it collapsed outside Mumbai in August 2015. Nine people had died the same month when another old three-storeyed building collapsed in monsoon rain in the Mumbai suburb of Thakurli.