"Responsibility for the attack" means that someone or a group is accountable for planning, carrying out, or being involved in an act of aggression or violence against others. Full definition
The political affiliation of respondents appeared to play a major role in their views of responsibility for the attacks. (sciencedaily.com)
ISIS claimed responsibility for those attacks on social media, and Trump tweeted that he'd ordered Homeland Security to «step up our already Extreme Vetting Program.» (relevantmagazine.com)