Gardaí have appealed for the public's help as they investigate the aggravated burglary at the home of a 96-year-old woman in the Buncrana area at the weekend.
Inspector David Murphy described the incident in which Margaret "Greta" Lilly was punched in the ribs and had money stolen from her as a "despicable act".
Inspector Murphy said gardaí have made some progress in the case.
They are asking anyone who was in the Aghilly and Tullydish areas early on Saturday morning to contact them at Buncrana Garda Station on 074-9320540.
People with information can also contact the Garda Confidential Line on 1800 666111.
Meanwhile, a Buncrana businessman has offered a reward of €5,000 for information leading to a prosecution in the case.
George McLaughlin said he has known Ms Lilly for many years and was so annoyed by the attack on her that he decided to put up the reward.