Lester Holt

Jamil's body had been found about 25 miles from campus on the Howard-Frankland Bridge, and a man was taken into custody and charged with killing not just Jamil, but Nahida too.

Who was the alleged killer, and how did he know them?

Joining me now to bring us up to speed on this fast-moving investigation is NBC News correspondent Jesse Kirsch.

Jesse, thanks for being here.

You bet.

Great to be with you.

So to start, tell us about these two young people.

And it wasn't just their family who noticed something was wrong.

People close to the students began to raise red flags, we understand.

Yeah, that sounds very alarming.

And I know university police were seeking help from wherever they could get it.

They contacted local police, the Hillsborough County Sheriff's Office, and their officers began interviewing anyone who might have information, who might know more.

So, Jesse, according to investigators, if I understand it, the real breakthrough in their case was when they took a closer look

and Hisham's movements around the time the students disappeared.

And then the Hillsborough County Sheriff's Office held a press conference to announce what they found.

Yeah, and in a motion filed by prosecutors over the weekend, we learned that investigators found what they believe is evidence of some kind of violent encounter at their apartment.

We're also learning that Hisham's phone showed potentially incriminating searches, which prosecutors are saying suggest these murders were premeditated.

So Hisham was arrested last Friday, and we should say Hisham has denied any involvement in the murders and has yet to enter a plea to the charges against him.

But is there anything more we know about him at this time, Jesse, and why he would allegedly do this?

And what about Hisham's relationship with Jamil and Nahida?