Jessica Mendoza

Zhang Youxia climbed the ranks of the People's Liberation Army, while Xi Jinping became a statesman.

Zhang would rise to the rank of general in 2011, and Xi would take his seat at the head of the country two years later.

And they stayed close.

Zhang is 75 years old.

How important has Zhang been to the military?

But late last month, it became obvious that the relationship had changed.

On January 24th, China's Ministry of National Defense made a shocking announcement.

General Zhang was under investigation.

Publicly, the government, which usually speaks through the state media, didn't say much.

Lingling wanted to know more about why Zhang was fired.

So she started making calls.

And Lingling learned that the morning before the announcement, a briefing took place, one that involved top military officials.

It was very secretive.

According to people familiar with the briefing, Zhang is under investigation for various crimes against the Chinese state and the Communist Party.

The most serious allegation is that Zhang had been leaking nuclear weapons secrets to the United States.

What did that look like as far as we know?

What was Zhang allegedly giving the U.S.?

There were other allegations as well.

Authorities called Zhang corrupt, accusing him of taking bribes.

And they accused him of forming what the Chinese Communist Party refers to as political cliques.