MUMBAI, India — The Mumbai police on Wednesday arrested a man affiliated with a local political party, accusing him of making illegal alterations to the ground floor of a five-story building that caused it to collapse a day earlier, killing at least 17 people and injuring a dozen others.

Deven Bharti, joint commissioner of the Mumbai police, said charges of culpable homicide and endangering the lives of others had been filed against the man, Sunil Shitap. Mr. Bharti said the police believed that Mr. Shitap had been making illegal alterations to the ground floor of the building, where he operated a nursing home, in Ghatkopar, an area east of the city center.

Relatives of the victims and other residents of the building said Mr. Shitap was affiliated with Shiv Sena, a local party. His wife, Swati Shitap, contested and lost local elections earlier this year as a member of the party.

“He had three flats on the ground floor that he emptied and broke the foundational pillar, which is why the building fell,” Vandana Singh, 45, who had lived in the building for nine years, said in an interview.