From the New York Times news section:
American officials said they were not aware of the plan ahead of time for the attack that killed Daria Dugina and that they had admonished Ukraine over it.
By Julian E. Barnes, Adam Goldman, Adam Entous and Michael Schwirtz
Oct. 5, 2022
WASHINGTON — United States intelligence agencies believe parts of the Ukrainian government authorized the car bomb attack near Moscow in August that killed Daria Dugina, the daughter of a prominent Russian nationalist, an element of a covert campaign that U.S. officials fear could widen the conflict.
The United States took no part in the attack, either by providing intelligence or other assistance, officials said. American officials also said they were not aware of the operation ahead of time and would have opposed the killing had they been consulted. Afterward, American officials admonished Ukrainian officials over the assassination, they said.
The closely held assessment of Ukrainian complicity, which has not been previously reported, was shared within the U.S. government last week….
American officials have been frustrated with Ukraine’s lack of transparency about its military and covert plans, especially on Russian soil.
Since the beginning of the war, Ukraine’s security services have demonstrated their ability to reach into Russia to conduct sabotage operations. …
Some American officials suspect Ms. Dugina’s father, Aleksandr Dugin, a Russian ultranationalist, was the actual target of the operation, and that the operatives who carried it out believed he would be in the vehicle with his daughter.
Mr. Dugin, one of Russia’s most prominent voices urging Moscow to intensify its war on Ukraine, has been a leading proponent of an aggressive, imperialist Russia.
… United States officials briefed on the Ukrainian action and the American response spoke on the condition of anonymity, in order to discuss secret information and matters of sensitive diplomacy.
My guess would be that the Biden Administration leaked this news about the Dugina assassination being a Ukrainian operation to imply to Germany that the Nord Stream pipeline bombing might well have been a Ukrainian operation.
… The United States has pressed Ukraine to share more about its war plans, with mixed success. Earlier in the war, U.S. officials acknowledged that they often knew more about Russian war plans — thanks to their intense collection efforts — than they did about Kyiv’s intentions.
Cooperation has since increased. During the summer, Ukraine shared its plans for its September military counteroffensive with the United States and Britain.
It’s hardly uncommon in history for smaller countries’ aggressiveness to trouble their larger allies: e.g., Serbia led Russia into the Great War in 1914. And Israel has done things that angered the U.S., like revealing the revolutionary American development of the capability to wipe out Soviet ground radar systems from the air by using an Israeli version of it to wipe out Syrian air defenses in the Bekaa Valley of Lebanon in 1982.