Sometimes, as occasion demanded, The Squad was strengthened by members of the IRA Intelligence Staff, the Active Service Unit, munition workers and members of the Dublin Brigade, Tipperary Flying Column men, Dan Breen, Séumas Robinson, Seán Treacy and Seán Hogan, and also Mick Brennan and Michael Prendergast of County Clare. The IRA Intelligence Staff consisted of the Director of Intelligence Michael Collins, the Deputy Director of Intelligence Liam Tobin, the Second Deputy Director of Intelligence Tom Cullen, the Third Director of Intelligence Frank Thornton, and members Joe Dolan, Frank Saurin, Ned Kelleher, Joe Guilfoyle, Paddy Cadwell, Paddy Kennedy, Charlie Dalton, Dan McDonnell and Charlie Byrne. The munitions workers included Mat Furlong, Sean Sullivan, Gay McGrath, Martin Kelly, Tom Younge and Chris Reilly.