Thanks A Lot, Mom. I Thought You Had My Back.

The mother of a suspect accused in a string of subway robberies and assaults turns in her son to authorities:

The mother acted a day after cops released a photo of Brian Ballard, 18, saying he was suspected in five robberies at three stations in two months.

Ballard was arrested at her home on Evergreen Avenue in Soundview and was charged with robbery and criminal use of a firearm, the sources said.

The teen, who has prior arrests for marijuana possession and robbery, allegedly punched and robbed riders inside the stations.