Pro-Ukrainian group blew up controversial Russian gas pipelines, but it's unclear who sent them, reports say

• A pro-Ukrainian group was behind the Nord Stream pipeline sabotage, per new reports.
• But it's still unclear who sent the group to carry out the underwater bombings. 
• The pipelines were controversial even before Russia launched the war in Ukraine.

A pro-Ukrainian group was responsible for the undersea sabotage of the Nord Steam pipelines last September, according to new intelligence reviewed by US officials that was first reported on by the New York Times.