"To release the suspect" means to set free or let go the person who is thought to be involved in a crime, usually because there is not enough evidence to keep them in custody or they are no longer considered a threat. Full definition
They did not release the suspect's name but said he is a local resident. (businessinsider.com)
Hotheaded dad Hugh Jackman wants answers and isn't above some abduction himself — of released suspect Paul Dano, adding memorably to his onscreen collection of effete creeps. (timeout.com)
San Francisco, meanwhile, has adjusted its policy to notify ICE if they are releasing suspected undocumented immigrants who face charges of serious or violent felonies. (businessinsider.com)