The five-alarm fire at a Bronx apartment building earlier this month that forced the evacuation of hundreds of residents and left the roof nearly completely collapsed was caused by problems with the electrical wiring, fire officials said this week — which also caused recent fires at two other buildings owned by the same landlord.

The three buildings are owned by Ved Parkash, who was named the worst landlord in New York City in 2015 by Letitia James, who was then the city’s public advocate and is now the state attorney general. Mr. Parkash is the target of continuing litigation over the condition of his buildings.

The six-story Bronx building where this month’s fire occurred, at 2910 Wallace Avenue, had been the subject of more than 400 complaints over the past two years, according to the Department of Housing Preservation and Development, which monitors the conditions of residential buildings in the city. Many of the complaints focused on a lack of heat or hot water and the presence of pests, including rats.

Mr. Parkash’s company, Parkash Management, said through a spokesman that its portfolio was full of prewar buildings in the most underserved neighborhoods of the Bronx, “aging properties in which breakdowns are frequent and require attention, repairs and upgrades on a constant basis.”

The company said that one of the other buildings it owns where a fire occurred had since been restored and was fully occupied, and that it was in the process of rehabilitating the other building. It added that the “dubious status of a decade ago, unfortunately, will always be raised by those who would rather call us the problem, instead of working with us as the solution to the housing shortage in the Bronx.”

The revelations about the landlord’s history, previously reported by The Bronx Times and The City, revived scrutiny of New York’s aging housing stock and the city’s ability to make sure people are not living in substandard conditions.