Here’s a brief look at some of the top news stories around the world for May 21, 2015.

Pizza crust leads to suspect in D.C. mansion fire

Authorities say DNA found on a pizza crust has led to the arrest of a suspect in the brutal murder of a "prominent" Washington, D.C. family earlier this month. 34-year-old Daron Dylon Wint is now in custody.

[Read more from CNN]

ISIS seizes ancient Syrian city

Reports say the Islamic State, a militant terrorist group operating in Syria and Iraq, has seized the historic city of Palmyra, home of many important archaeological sites.

[Read more from The New York Times]

Biologists determining damage of California oil spill

Experts say it could take weeks to clean up the mess left from a massive leak at an oil facility, which is believed to have dumped 105,000 gallons of crude into the ocean off Santa Barbara. Meanwhile, environmentalists are assessing the damage to the ecosystem.

[Read more from NBC News]