Death Eaters
Alecto passed out from heavy blood loss and pain due to a number of injuries, most notably the impalement in the shoulder and a shattered knee cap. Rabbit found her and brought her to the Lestrange Manor, where she stayed until she woke up, which probably wasn't until at least Monday evening, possibly later.
Once she wakes up and firgures out where she is, she'll be incredibly grateful to the Lestranges for their hospitality, especially Rabbit.