Actually, according to what I read on the web site of the Death Penalty Information Center, any federal prosecutor wanting to prosecute under the death penalty has to get "personal written permission from the Attorney General of the United States. Apparently, this may be due to the "seemingly racial bias"  in federal death penalty cases. The defendant in this case is not black but he is Hispanic. 
So, it might be Jeff Session whose has the final say if the prosecutor decides to go for the death penalty. 
Have no idea if this man had any prior convictions or if he is a pillar of the community. 
My guess is that they will not go for the death penalty. Of course, they might decide to make a "statement" about domestic violence (which would be great) and this case does fall under VAWA. That might be a way to "say" Trump takes violence against women seriously, political move? 
What do you think ?