Did Rep. Michael Grimm apologize to NY1 reporter to head off criminal prosecution for assault?

NY1

This is the exchange between the reporter and Rep. Grimm:

"I'm not speaking to you off-topic, this is only about the president," said Grimm, before walking off camera.

"So Congressman Michael Grimm does not want to talk about some of the allegations concerning his campaign finances," Scotto said before tossing back to the station. But as the camera continued to roll, Grimm walked back up to Scotto and began speaking to him in a low voice.

"What?" Scotto responded. "I just wanted to ask you..."

Grimm: "Let me be clear to you, you ever do that to me again I'll throw you off this f-----g balcony."

Scotto: "Why? I just wanted to ask you..."

[[cross talk]]

Grimm: "If you ever do that to me again..."

Scotto: "Why? Why? It’s a valid question."

[[cross talk]]

Grimm: "No, no, you're not man enough, you're not man enough. I'll break you in half. Like a boy."

I did a little checking and simple assault in in Washington D.C. is as follows: 

 “Assault” is defined generally as the threat or use of force on another person that causes that person to have reasonable apprehension of imminent harmful or offensive contact.  Assault can be a civil wrong (or “tort”). 

I’d say threatening to throw somebody of a balcony and rip them into two like a little boy constitutes enough evidence as shown in the video that Congressman Grimm at most threatened the NY1 reporter’s life or at least is guilty of coming the crime of assault under the criminal code of Washington D.C. 

Congressman Grimm broke the law and should be prosecuted and if not why not?  Are politicians above the law even though there is video proof of the crime?