The Joint Parliamentary Committee on the 2G spectrum allocation scam is set to question the Director of the Enforcement Directorate at its meeting scheduled for Tuesday. It may devote the rest of its time to finalising a list of all witnesses, from the NDA and UPA regimes, who need to be called. The JPC has met infrequently — just 39 times since it was constituted in February 2011 — and secured the oral evidence of 14 non-official witnesses, who held office in the Department of Telecom (DoT) and the Telecom Regulatory Authority of India (TRAI), as well as that of the Finance Ministry, the Comptroller and Auditor-General and the Central Bureau of Investigation.