The 24-year-old was originally from Nicaragua and lived on Black Rock Avenue with her infant daughter.
Police say the 1-year-old was found unharmed on the front porch of a home and near her mother's body. She was left there by the suspect, police say.
The child is now staying with a family member.
Police have not released any information about the suspect.
While police say they are still establishing a motive, they have not ruled out domestic violence.
Detectives have also received strong leaders and significant help from the community. They are currently reviewing a large amount of surveillance videos.
Police say this is an isolated incident and that there is no danger to the public.
Anyone with information is asked to call police at 203-581-5291.