Connecticut Killer Cannibal Victim's Family Believes He'll Kill Again After Release

TMZ also recently spoke to Jeffrey Dahmer investigator Dennis Murphy ... who warned Smith could fall back into his murderous ways -- just like Dahmer, who vowed to kill and eat people again if he were ever released from prison ... before his own 1994 slaying behind bars.

Talitha says she agrees with Dahmer's assessment, pointing out Smith will likely act out again.

She tells us, "[The] only way to protect our society -- he should have been kept behind closed doors."