New York City police officers lined city streets to honor their colleague who was killed when a gunman entered a Midtown Manhattan office building and opened fire earlier this week.Officer Islam was one of four people killed inside the building on Monday evening.

An active shooter incident occurred in Midtown Manhattan, New York, officials said. Here's what to know about 345 Park Ave.

The office building, located at 345 Park Avenue, houses some of the country’s top financial firms, including Blackstone, and the National Football League. According to the company's website, Blackstone stands as the world’s largest alternative asset manager, managing over $1 trillion in assets under management.