From CNN, I'm Charlie Drever, with the five things you need to know for Monday, December 9th.

As the Assad regime falls and rebels take control of Syria, people are asking what's next for the country.

Syrian people have been celebrating in the streets of the newly captured capital city Damascus and around the world.

The rebel coalition that toppled the regime are made up of different ideologies,

with one shared goal of getting rid of President Bashar al-Assad.

But now that Assad resigned and fled to Russia, it's not clear how Syria will be ruled.

President Joe Biden described it as a moment of opportunity, but also a moment of risk,

and US forces launched strikes at ISIS targets in Syria yesterday,

over concerns that Islamic extremism could rise.

And Syria's neighbour, Israel, has said it's carried out airstrikes in the country,

as well as sending troops across the border, which is where CNN's Jeremy Diamond is.

There is a buffer zone of about two kilometers where Israeli troops have not been positioned for more than 50 years,

but now Israeli troops are inside that buffer zone.

And we're also told, according to the Israeli Defense Ministry, that Israeli troops have also

captured positions beyond that buffer zone as well in a Syrian-held territory.

Police are still missing key pieces of evidence as the hunt continues for the man who shot

and killed United Healthcare CEO in New York last week.

Authorities still haven't publicly identified the shooter, and divers spent the weekend

searching a pond in Central Park to try and find the murder weapon, without success.

But police have gathered some clues,

like a backpack containing monopoly money and the suspect's jacket,

images of the man's face, and DNA from a discarded Starbucks water bottle.

...