Two senior citizens died after after a portion of a concrete slab of a four-storied residential building collapsed on them. The incident was reported around 8.15 pm on Thursday evening at a housing society in Ramabai Ambedkar Udyan at Vikhroli (East). The deceased have been identified as Sharad Mhaslekar (75) and Suresh Madhalkar (78). "The slab collapsed on the compound of the residential building where the two were present. The victims were residents of the building which was partly occupied. They were immediately transported to the hospital nearby where they were declared dead," said an official from the local BMC ward office. The officials said the building, built by MHADA, was more than twenty years old, owing to which many residents had relocated elsewhere. Civic officials said they will be writing to MHADA authorities asking them to carry out a structural audit of the building.