[El Cid]

My take is that Cesar was somebody's patsie. Not meaning to be insulting, but he came across as mentally challenged. There was a rather large kerfuffle when this came up a year ago (roughly) and it turned out that he sent nothing really 'dangerous'. Inactive 'stuff' that appeared to be dangerous. It was weird, because the person who sent it knew he'd be in big trouble - even if the stuff was basically harmless. I say 'basically' because the recipient would not know the stuff was fake, and he could have suffered a fatal heart attack. If nothing else - the diversion of important resources might have allowed real crimes to occur elsewhere.
Nonetheless, 20 years seems awfully harsh - and I'd still like to know who put him up to this lame-brain idea.

[nvcdl]

He is friends with a former CIA agent/ drug gang member.

https://www.dcclothesline.com/2018/10/30/wondered-why-all-those-trump-stickers-on-fake-maga-bombers-van-were-so-pristine-heres-why/

[robowombat]

Cesar was someone in the FBI or BATF’s sock puppet. Screwed up guy with a life script of loser and failure. Just the sort of confused angry and unintelligent type to manipulate. The deep state has moved on to real murder and mayhem as witnessed in El Paso.