An elderly couple was drugged and robbed of jewellery and cash amounting to Rs 20 lakh on Thursday allegedly by their unverified domestic help,hired a day before the incident in Vikaspuri,West Delhi. The police,who reportedly recovered liquor bottles and a dagger from the M-Block house,claim the attack was pre-planned. According to the police,the victims N R Dogra (65),a retired government servant,and his wife Kavita (59) were served dinner laced with sedatives by their domestic help,identified as Vikram alias Mama. The Nepalese domestic help was hired on January 26, said an officer. The employers had not filled the mandatory servant verification form,he added. The 25-year-old accused was referred to them by one of colonys security guards.