Collins himself was in Cork at the time of the crisis. President Arthur Griffith and military officer Emmet Dalton met with British official to discuss 'the continued occupation of the Four Courts by the Irregulars under Rory O'Connor'. There is little documentation of the decision taken by the Provisional government, headed by Collins, to attack the Four Courts; Historian Michael Hopkinson writes, 'the scarcity of evidence is explained by the acute sensitivity of the subject, both at the time and since'. When Collins arrived back in Dublin, his forces began to act against the anti-Treatyites. On 27 June they arrested anti-Treaty IRA officer Leo Henderson as he was enforcing the Belfast Boycott by seizing cars. In retaliation the anti-Treaty IRA men abducted J.J. "Ginger" O'Connell, a Free State general and held him in the Four Courts.