Police have registered a case and licensed pistol has been seized.
Woman allegedly opened fire at her mother and brother at their South Delhi Defence Colony residence around Thursday night.
Starting probe revealed that the accused Sangeeta (47-year-old) was in an inebriated state and police said the victims, Geeta and her son Harsaran, are out of danger.
Cops suspect the incident could be the result of a property dispute.
They had a heated argument after which the accused opened fire, said police.
Under section 307 of the IPC (attempt to murder), a case has been registered and further probe is on.