If by "highest" you mean nineteeth in this year's tally so far, then....I....guess?
https://freedomforallamericans.org/highest-murders-in-us-by-...
St. Louis, MO's rate was 69 per 100k and DC was 17 per 100k.
St. Louis has a murder rate four times DC, yet curiosly no talk of deploying the FBI and national guard there.
St. Louis situation is absolutely abysmal. 20 is way too high, 69 is way too high. These are 3rd world numbers that are absolutely inexcusable. And we're only talking about murders here, if you look into other violent crime data, it's also substantial for D.C.
The FBI frequently gets involved in murder cases all over the country, there are field offices everywhere. States are significantly different things than the special federal District of Columbia. There, it is generally up to the Governor to deploy the national guard, although plenty of exceptions and precedents exist for the President to do so.
https://apnews.com/article/national-guard-los-angeles-immigr...
It's now winding its way through the appeals process.
Legally, there are exceptions to that (primarily the Insurrection Act, though there are some deployments that are permitted within states on federal authority on other legal bases with tightly-constrained functions), and practically, the legal limits don't matter because response time off the courts is to slow for them to act as a meaningful brake. (E.g., the lawsuit filed the first court day after the order to mobilize the guard for LA just reached the trial stage this week.)
But critically, the trial in which the legality of that action is considered is happening the week. Whether or not the action is judged to have been a constitutional violation ultimately doesn't matter; the administration did it, and even if the court rules against the administration, it will have been two months too slate. Effectively, the president has demonstrated he can federalize the national guard whether or not the governor consents for long enough to score whatever political/media points he's currently fixated on, and if the legal system stops him, he will have moved on to other issues.
https://apnews.com/article/california-trump-national-guard-l...
Pretty sure that doesn't apply in LA in 2025.
Widespread poverty and guns.
The cause is not "poverty and guns," because Idaho, which has a lot of poverty and a ton of guns, has one-third the homicide rate of Maryland, which is one of the richest and most educated states.